docksal: fin update doesn't install dependencies, only self-updates, on Windows 10 64-bit by default

Description

I cannot use docksal on a Windows 64-bit system because

1. babun does not have a stable 64-bit release / process.
2. cygwin64 does have a stable 64-bit release that babun’s documentation recommends to use instead of babun, but docksal is having issues detecting custom commands or running update.

Steps to reproduce the issue:

With babun

1. Try to install babun
2. Get Unexpected error message. Give up. Do not use docksal?

With cywgin64

1. Install cygwin64 via 64-bit installer. Make sure to include php and curl packages that are required for Drupal 8.4 core development.
2. Downloaded fin shell script to C:\cygwin64\usr\local\bin\.
3. Tried running fin vm start per instructions. Failed beacuse docker not available.
4. Tried running fin update per failed command above’s recommendation. Fails to run fin update because the update command uses sudo instead of trying the winsudo function that fin defines.
5. Tried just running fin init:
   • git clone https://github.com/BrianGilbert/docksal-core-sprint
   • cd docksal-core-sprint
   • fin init
6. Try hacking fin shell script and keep running into hard errors. Give up.

Describe the results you received:

Tried to run fin vm start per docksal instructions…

$ fin vm start
docker-machine executable was not found. (Try running 'fin update')

Okay, now I tried fin update…

$ fin update
Updating fin...
/usr/local/bin/fin: line 3222: sudo: command not found
 ERROR:  Could not write /usr/local/bin/fin.updated

Okay, let’s hack the update function to use winsudo instead…

$ fin update
Updating fin...
/usr/local/bin/fin: line 3231: /usr/local/bin/fin.updated: No such file or directory
fin  downloaded...
/usr/local/bin/fin: line 3235: /usr/local/bin/fin.updated: No such file or directory

Describe the results you expected:

I expect that I can use docksal on a Windows 10 64-bit system because the System Requirements for docksal do not mention needing to use 32-bit binaries.

Output of fin config:

$ fin config output
 ERROR:  No configuration files found.
         Expected in C:/cygwin64/c/dev/docksal-core-sprint/.docksal/docksal.yml

Output of fin sysinfo:

$ fin sysinfo
███  OS & BASICS
CYGWIN_NT-10.0 MACHINENAME 2.8.2(0.313/5/3) 2017-07-12 10:58 x86_64 Cygwin
Microsoft Windows [Version 10.0.14393]
fin version: 1.26.2
Mode:  VirtualBox VM
███  DOCKER
DOCKER_HOST:

/usr/local/bin/fin: line 3952: docker: command not found
Docker:
███  DOCKER COMPOSE
/usr/local/bin/fin: line 3955: docker-compose: command not found
Docker Compose:
███  VIRTUALBOX
5.1.26r117224
███  NETWORK INTERFACES
Name:            VirtualBox Host-Only Ethernet Adapter #4
GUID:            b9fa8fae-681d-43c6-a9e0-a6a7bf345a3c
DHCP:            Disabled
IPAddress:       192.168.253.1
NetworkMask:     255.255.255.0
IPV6Address:     fe80:0000:0000:0000:8c39:7422:7a53:ad4b
IPV6NetworkMaskPrefixLength: 64
HardwareAddress: 0a:00:27:00:00:0a
MediumType:      Ethernet
Status:          Up
VBoxNetworkName: HostInterfaceNetworking-VirtualBox Host-Only Ethernet Adapter #4

Name:            VirtualBox Host-Only Ethernet Adapter #3
GUID:            fe6eed92-3843-477c-aec9-5b3d5de3869b
DHCP:            Disabled
IPAddress:       192.168.56.1
NetworkMask:     255.255.255.0
IPV6Address:     fe80:0000:0000:0000:59d7:c791:196f:97b1
IPV6NetworkMaskPrefixLength: 64
HardwareAddress: 0a:00:27:00:00:0c
MediumType:      Ethernet
Status:          Up
VBoxNetworkName: HostInterfaceNetworking-VirtualBox Host-Only Ethernet Adapter #3