ci: enable update_pcu in label job to test fix (#135)

## Summary
- Enables `update_pcu: true` in the `toolkit/label` job to install pcu
from GitHub main branch
- This tests the fix for the label_next_pr filter bug
(jerus-org/pcu#788)

## Test plan
- [ ] Merge this PR to main
- [ ] Verify the label job runs and adds "rebase" label to oldest
renovate PR

🤖 Generated with [Claude Code](https://claude.com/claude-code)

.circleci/config.yml

@@ -52,6 +52,7 @@ workflows:
       - toolkit/label:
           min_rust_version: << pipeline.parameters.min_rust_version >>
           context: pcu-app
+          update_pcu: true
           filters:
             branches:
               only:

PRLOG.md

@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - ♻️ refactor(cli)-rename rule management subcommands for clarity(pr [#113])
 - 🔧 chore(dependencies)-clap test and tidy ups(pr [#114])
+- ci-enable update_pcu in label job to test fix(pr [#135])
 
 ### Fixed
 
@@ -391,6 +392,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 [#125]: https://github.com/jerus-org/cull-gmail/pull/125
 [#126]: https://github.com/jerus-org/cull-gmail/pull/126
 [#129]: https://github.com/jerus-org/cull-gmail/pull/129
+[#135]: https://github.com/jerus-org/cull-gmail/pull/135
 [Unreleased]: https://github.com/jerus-org/cull-gmail/compare/v0.0.16...HEAD
 [0.0.16]: https://github.com/jerus-org/cull-gmail/compare/v0.0.15...v0.0.16
 [0.0.15]: https://github.com/jerus-org/cull-gmail/compare/v0.0.14...v0.0.15