feat(appset): add filter titleMatch to PullRequest generator

[jjsiv]

Fixes #16447

This PR adds a titleMatch filter to the ApplicationSet's pull request generator.

Checklist:

• Either (a) I've created an enhancement proposal and discussed it with the community, (b) this is a bug fix, or (c) this does not need to be in the release notes.
• The title of the PR states what changed and the related issues number (used for the release note).
• The title of the PR conforms to the Toolchain Guide
• I've included "Closes [ISSUE #]" or "Fixes [ISSUE #]" in the description to automatically close the associated issue.
• I've updated both the CLI and UI to expose my feature, or I plan to submit a second PR with them.
• Does this PR require documentation updates?
• I've updated documentation as required by this PR.
• Optional. My organization is added to USERS.md.
• I have signed off all my commits as required by DCO
• I have written unit and/or e2e tests for my change. PRs without these are unlikely to be merged.
• My build is green (troubleshooting builds).
• My new feature complies with the feature status guidelines.
• I have added a brief description of why this PR is necessary and/or what this PR solves.

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (19fa5b9) 49.50% compared to head (1d77f72) 49.52%.

Files	Patch %	Lines
applicationset/services/pull_request/github.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #16499      +/-   ##
==========================================
+ Coverage   49.50%   49.52%   +0.01%     
==========================================
  Files         269      269              
  Lines       47430    47444      +14     
==========================================
+ Hits        23479    23495      +16     
+ Misses      21645    21644       -1     
+ Partials     2306     2305       -1     

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[ggjulio]

@jjsiv I'm interested by that feature.

What are the missing bits to make it work ?
Or maybe you found a workaround to filter bitbucket PRs other than by branch name ?

EDIT

I opened a draft PR #17907 that only add the key title for all SCMaaS providers.
It should be good enough to filter PRs by title using the workaround from crenshaw-dev #16447 (comment)