pages-gem: gh-pages version and jekyll version problem

I’m having a version problem when I do install or update. Instead of getting gh-pages 104 and jekyll 3.3.0, I’m getting 35/39 and 2.4.0

I do as follows

$ jekyll new darkhollow.github.io

And get

New jekyll site installed in /Users/roberto/Proyectos/darkhollow.github.io. 
Running bundle install in /Users/roberto/Proyectos/darkhollow.github.io... 
Fetching gem metadata from https://rubygems.org/...........
Fetching version metadata from https://rubygems.org/..
Fetching dependency metadata from https://rubygems.org/.
Resolving dependencies...
Using public_suffix 2.0.3
Using colorator 1.1.0
Using ffi 1.9.14
Using forwardable-extended 2.6.0
Using sass 3.4.22
Using rb-fsevent 0.9.8
Using kramdown 1.12.0
Using liquid 3.0.6
Using mercenary 0.3.6
Using rouge 1.11.1
Using safe_yaml 1.0.4
Using minima 2.0.0
Using bundler 1.13.6
Using addressable 2.5.0
Using rb-inotify 0.9.7
Using pathutil 0.14.0
Using jekyll-sass-converter 1.4.0
Using listen 3.0.8
Using jekyll-watch 1.5.0
Using jekyll 3.3.0
Using jekyll-feed 0.8.0
Bundle complete! 3 Gemfile dependencies, 21 gems now installed.
Use `bundle show [gemname]` to see where a bundled gem is installed.

And then

$ cd darkhollow.github.io/
$ vim Gemfile 

and I comment the line: gem "jekyll", "3.3.0" and I uncomment the line: gem "github-pages", group: :jekyll_plugins

Finally I do

$ bundle update

and I get this

Fetching gem metadata from https://rubygems.org/..................
Fetching version metadata from https://rubygems.org/...
Fetching dependency metadata from https://rubygems.org/..
Resolving dependencies...
Using RedCloth 4.2.9
Using concurrent-ruby 1.0.2
Using i18n 0.7.0
Using minitest 5.9.1
Using thread_safe 0.3.5
Using addressable 2.4.0 (was 2.5.0)
Using blankslate 2.1.2.4
Using fast-stemmer 1.0.2
Using coffee-script-source 1.10.0
Using execjs 2.7.0
Using colorator 0.1 (was 1.1.0)
Using ffi 1.9.14
Using multipart-post 2.0.0
Using gemoji 2.1.0
Using net-dns 0.8.0
Using public_suffix 1.5.3 (was 2.0.3)
Using jekyll-paginate 1.1.0
Using sass 3.4.22
Using rb-fsevent 0.9.8
Using kramdown 1.5.0 (was 1.12.0)
Using liquid 2.6.2 (was 3.0.6)
Using mercenary 0.3.6
Using posix-spawn 0.3.12
Using yajl-ruby 1.2.1
Using redcarpet 3.1.2
Using safe_yaml 1.0.4
Using mini_portile2 2.1.0
Using jekyll-sitemap 0.8.1
Using maruku 0.7.0
Using rdiscount 2.1.7
Using unicode-display_width 1.1.1
Using jekyll-feed 0.7.2 (was 0.8.0)
Using minima 2.0.0
Using bundler 1.13.6
Using tzinfo 1.2.2
Using parslet 1.5.0
Using classifier-reborn 2.0.4
Using coffee-script 2.4.1
Using ethon 0.9.1
Using rb-inotify 0.9.7
Using faraday 0.9.2
Using jekyll-sass-converter 1.2.0 (was 1.4.0)
Using pygments.rb 0.6.1
Using nokogiri 1.6.8.1
Using terminal-table 1.7.3
Using activesupport 5.0.0.1
Using toml 0.1.2
Using jekyll-coffeescript 1.0.1
Using typhoeus 0.8.0
Using listen 3.0.8
Using sawyer 0.7.0
Using html-pipeline 1.9.0
Using github-pages-health-check 0.3.2
Using jekyll-watch 1.5.0
Using octokit 4.4.1
Using jekyll-gist 1.4.0
Using jekyll 2.4.0 (was 3.3.0)
Using jekyll-mentions 0.2.1
Using jekyll-redirect-from 0.6.2
Using jemoji 0.4.0
Using github-pages 35
Bundle updated!

So jekyll goes back to 2.4.0 version and github-pages to 35 version.

If I delete the Gemfile.lock and do bundle install it gets the same versions.

And if I serve I get an error, I do

$ bundle exec jekyll serve

and get

  Configuration file: /Users/roberto/Proyectos/darkhollow.github.io/_config.yml
              Source: /Users/roberto/Proyectos/darkhollow.github.io
         Destination: /Users/roberto/Proyectos/darkhollow.github.io/_site
        Generating... 
       Build Warning: Layout 'post' requested in _posts/2016-11-05-welcome-to-jekyll.markdown does not exist.
    Liquid Exception: Included file '_includes/icon-github.html' not found in about.md
jekyll 2.4.0 | Error:  Included file '_includes/icon-github.html' not found

I guess it’s for the old versions I get when I do update

Last try, if I only write in the Gemfile source and the github pages gem, I get this versions

Fetching gem metadata from https://rubygems.org/...........
Fetching version metadata from https://rubygems.org/..
Fetching dependency metadata from https://rubygems.org/.
Resolving dependencies....
Using RedCloth 4.2.9
Using concurrent-ruby 1.0.2
Using i18n 0.7.0
Using minitest 5.9.1
Using thread_safe 0.3.5
Using addressable 2.4.0
Using blankslate 2.1.2.4
Using fast-stemmer 1.0.2
Using coffee-script-source 1.10.0
Using execjs 2.7.0
Using colorator 0.1
Using ffi 1.9.14
Using multipart-post 2.0.0
Using gemoji 2.1.0
Using net-dns 0.8.0
Using public_suffix 1.5.3
Using jekyll-paginate 1.1.0
Using sass 3.4.22
Using rb-fsevent 0.9.8
Using kramdown 1.5.0
Using liquid 2.6.2
Using mercenary 0.3.6
Using posix-spawn 0.3.12
Using yajl-ruby 1.2.1
Using redcarpet 3.3.2
Using safe_yaml 1.0.4
Using jekyll-feed 0.3.1
Using mini_portile2 2.1.0
Using jekyll-sitemap 0.8.1
Using maruku 0.7.0
Using rdiscount 2.1.7
Using unicode-display_width 1.1.1
Using bundler 1.13.6
Using tzinfo 1.2.2
Using parslet 1.5.0
Using classifier-reborn 2.0.4
Using coffee-script 2.4.1
Using ethon 0.9.1
Using rb-inotify 0.9.7
Using faraday 0.9.2
Using jekyll-sass-converter 1.3.0
Using pygments.rb 0.6.3
Using nokogiri 1.6.8.1
Using terminal-table 1.7.3
Using activesupport 5.0.0.1
Using toml 0.1.2
Using jekyll-coffeescript 1.0.1
Using typhoeus 0.8.0
Using listen 3.0.8
Using sawyer 0.7.0
Using html-pipeline 1.9.0
Using github-pages-health-check 0.3.2
Using jekyll-watch 1.5.0
Using octokit 4.4.1
Using jekyll-gist 1.4.0
Using jekyll 2.4.0
Using jekyll-mentions 0.2.1
Using jekyll-redirect-from 0.8.0
Using jemoji 0.5.0
Using github-pages 39
Bundle updated!