ci: switch to release please and deprecate github pat

[subzero10]

• Adds release-please-action, which enables:
  • Automatic versioning with conventional commits
  • Automatic CHANGELOG.md generation
• Adds workflow to check the PR title for conventional commit syntax
• Remove expublish dependency

Notes:

• Release-please integration changes the release flow in a way that bots do not commit directly to the main branch, therefore eliminating the need for a GitHub Personal Access Token (or GitHub app).
• I also changed the allowed commit methods to be only squash (works well with conventional commits).
• I manually created the labels autorelease: created and autorelease: pending, which are required for the action to work with GITHUB_TOKEN.

[subzero10]

@rabidpraxis Can I please get your input on this PR? CI is failing and I'm thinking it's unrelated to my changes. This test is failing consistently with Elixir 1.17 and 1.18:

1. test samples for un-hashed values (Honeybadger.EventsSamplerTest)
   Error: test/honeybadger/events_sampler_test.exs:41
   Assertion with =~ failed
   code: assert log =~ ~r"[Honeybadger] Sampled \d events (of 3 total events)"
   left: "\n06:27:10.908 [debug] [Honeybadger] Failed to send events batch (attempt 2): "Other error"\n\n06:27:11.009 [debug] [Honeybadger] Failed to send events batch (attempt 3): "Other error"\n\n06:27:11.009 [debug] [Honeybadger] Dropping events batch after 3 attempts.\n\n06:27:11.009 [debug] [Honeybadger] Terminating with 0 events unsent\n\n06:27:11.009 [debug] [Honeybadger] Terminating with 0 events unsent\n\n06:27:11.060 [debug] [Honeybadger] Terminating with 2 events unsent\n\n06:27:11.412 [debug] [Honeybadger] Terminating with 0 events unsent\n\n06:27:11.513 [debug] [Honeybadger] Terminating with 0 events unsent\n"
   right: ~r/[Honeybadger] Sampled \d events (of 3 total events)/
   stacktrace:
   test/test_helper.exs:38: Honeybadger.Case.with_config/2
   test/honeybadger/events_sampler_test.exs:42: (test)

[Copilot]

Pull Request Overview

This PR modernizes the release automation workflow by migrating from the expublish tool to Google's release-please-action, and improves test reliability with better timing controls.

• Replaces manual expublish-based releases with automated release-please workflow
• Fixes test timing issues by reducing sleep duration and adding synchronous calls
• Updates dependencies and tooling to current versions

Reviewed Changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
test/honeybadger/events_sampler_test.exs	Optimizes test timing by reducing sleep from 1000ms to 110ms and adds synchronous call to ensure message processing
mix.exs	Removes expublish dependency no longer needed with new release workflow
mix.lock	Removes expublish and updates x509 to version 0.9.2
.github/workflows/publish.yml	Replaces manual workflow dispatch with automated release-please action for release management
.github/workflows/elixir.yml	Updates OTP version from 28.0 to 28.1 for the latest Elixir 1.18 test matrix
.github/workflows/check-pr-title.yml	Adds new workflow to validate PR titles follow conventional commit format

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[Copilot]

Pull Request Overview

Copilot reviewed 5 out of 6 changed files in this pull request and generated 2 comments.

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[subzero10]

This is ready, though I haven't tested it. Are we OK with merging and testing when we decide to do a release?
If so, I could take a small issue and submit a PR for it.

[stympy]

This is ready, though I haven't tested it. Are we OK with merging and testing when we decide to do a release? If so, I could take a small issue and submit a PR for it.

Yup!