ansible-role-nginx: incorrect repo for AWS ami

Describe the bug Trying to install nginx on an AWS ami To reproduce Steps to reproduce the behavior:

1. Deploy NGINX role using playbook.yml
2. Installs the centos/redhat repo
3. See errors

TASK [nginx : (Install: CentOS/RedHat) Install NGINX] ***************************************************************************************************************************************************************************************
fatal: [xx.xxx.xxx.xxx]: FAILED! => {"changed": false, "msg": "Failure talking to yum: failure: repodata/repomd.xml from nginx: [Errno 256] No more mirrors to try.\nhttps://nginx.org/packages/mainline/centos/NA/x86_64/repodata/repomd.xml: [Errno 14] HTTPS Error 404 - Not Found"}

Yum update error

failure: repodata/repomd.xml from nginx: [Errno 256] No more mirrors to try. https://nginx.org/packages/mainline/centos/NA/x86_64/repodata/repomd.xml: [Errno 14] HTTPS Error 404 - Not Found

Expected behavior To install nginx

Your environment:

• Version of the NGINX Role or specific commit latest

• Version of Ansible ansible 2.7.9

• Target deployment platform AMI flavour

$ cat /etc/os-release 
NAME="Amazon Linux AMI"
VERSION="2018.03"
ID="amzn"
ID_LIKE="rhel fedora"
VERSION_ID="2018.03"
PRETTY_NAME="Amazon Linux AMI 2018.03"
ANSI_COLOR="0;33"
CPE_NAME="cpe:/o:amazon:linux:2018.03:ga"
HOME_URL="http://aws.amazon.com/amazon-linux-ami/"

$ cat /etc/yum.repos.d/nginx.repo 
[nginx]
baseurl = https://nginx.org/packages/mainline/centos/NA/$basearch/
enabled = 1
gpgcheck = 1
name = NGINX Repository

Probably the path should have 7 instead of NA, maybe the CENTOS version is not detected properly.

I see that that supported OS for opensource version do not include AWS AMI linux, only the Nginx Plus - this could be the issue.