Several improvements

[GuySartorelli]

Commits

1. Add an option so we can run just a single script. Useful if for example someone updated all the crons on the next-minor branch, but you need to run a new script on the next-patch branch :p
2. Start from scratch when updating PRs. This means if there are changes in the previous PR that shouldn't be applied, you can rerun with --update-prs and it will remove those changes before running the scripts.
3. Add the new workflow if there's a action-ci.yml file, since gha-* repos don't have ci.yml
4. Added exclusions for modules that shouldn't get the new workflow
5. Fix bug where repos with wildcard mapping for CMS major wouldn't run again the next-patch branch

Issue

• Error when using workflow: ”The nested job 'genmatrix' is requesting 'pull-requests: read'“ gha-ci#137

[emteknetnz]

Please exclude the following modules from getting the workflow in the future, which have open PRs:

• cow
• module-standardiser
• silverstripe-tx-translator
• supported-modules
• api.silverstripe.org

Ditto for the following that have closed PRs:

• webpack-config
• silverstripe-userhelp-content
• silverstripe-simple

Also ensure any other "tooling" repos where you may have already deleted the PR is excluded

[GuySartorelli]

The ones with closed prs are already excluded, that's why I closed the prs.

[GuySartorelli]

Added exclusions.

[GuySartorelli]

Added an extra commit to fix a bug where repos with wildcard mapping for CMS major wouldn't run again the next-patch branch