Update workflow.yml & Gemfile

[MSP-Greg]

1. CI on Ubuntu & Windows, Ruby 2.5 thru master
2. Cache bundler
3. Update Gemfile for stdlib -> bundled gems

Notes

4. Windows is slower, will be helped when Actions adds MSYS2
5. CI has random failures. See PR client_spec.rb - fix random failures #1201

[MSP-Greg]

Actions' 'reporting' get mixed up when a workflow's jobs change.

JFYI, doc's for master branch are at https://msp-greg.github.io/octokit/. Normally updated daily...

[tarebyte]

Thanks for the PR @MSP-Greg, I don't think we want to support Ruby versions that are listed as unmaintained or EOL. That's out of scope for this gem.

Can we set that back to 2.5 - ruby-head ?

[MSP-Greg]

Change the gemspec also?

octokit.rb/octokit.gemspec

Line 19 in 9f19351

spec.required_ruby_version = '>= 2.0.0'

[tarebyte]

Change the gemspec also?

We'll do that on the v5 release

[MSP-Greg]

Can we set that back to 2.5 - ruby-head ?

Done.

Are 4-stable and master split?

If there will be more 4-stable releases, that branch (ideally) should have CI matching the gemspec version. This PR is against master right now. And, I did not add macOS testing, but normally for a straight ruby repo, if Ubuntu passes, macOS will also.

[MSP-Greg]

To allow work in fork branches, I added '*':

on:
   push:
     branches:
     - master
     - 4-stable
     - '*'

[MSP-Greg]

Should I close this and open a new PR to 4-stable? Never tried changing the destination branch, can't see an option to do so...

[MSP-Greg]

Closing in favor of PR #1206, which is the same thing but against 4-stable