Pin japicmp baseline in version.gradle.kts

[trask]

Pin the API diff baseline in version.gradle.kts and update it together with the API diff files after each release. This prevents a new release from breaking API diff checks on open PRs.

Port of open-telemetry/opentelemetry-java-instrumentation#18391.

#8587 (comment) made me remember this.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.60%. Comparing base (1588a31) to head (1b371e1).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #8591      +/-   ##
============================================
- Coverage     91.61%   91.60%   -0.01%     
+ Complexity    10315    10314       -1     
============================================
  Files          1013     1013              
  Lines         27274    27274              
  Branches       3202     3202              
============================================
- Hits          24986    24984       -2     
- Misses         1561     1562       +1     
- Partials        727      728       +1     

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[Copilot]

Pull request overview

This PR pins the japicmp “old” (baseline) version in version.gradle.kts and threads it through the build so API diff checks compare against a stable baseline that can be updated atomically after releases.

Changes:

• Introduces apidiffBaselineVersion in version.gradle.kts and exports it via extra for build logic.
• Updates the japicmp Gradle conventions to use the pinned baseline instead of dynamically resolving latest.release.
• Updates documentation and the release workflow to bump the pinned baseline alongside regenerated API diff files.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
version.gradle.kts	Adds pinned apidiffBaselineVersion and publishes it via extra.
docs/knowledge/build.md	Documents that API diffs compare against the pinned baseline.
buildSrc/src/main/kotlin/otel.japicmp-conventions.gradle.kts	Switches japicmp baseline resolution to the pinned version.
.github/workflows/release.yml	Updates post-release automation to pin the baseline to the newly released version.

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[trask]

will want to bump this to 1.64.0 after #8586 is merged

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated no new comments.