Bump golangci/golangci-lint-action from 5 to 6

Bumps [golangci/golangci-lint-action](https://github.com/golangci/golangci-lint-action) from 5 to 6.
- [Release notes](https://github.com/golangci/golangci-lint-action/releases)
- [Commits](golangci/golangci-lint-action@v5...v6)

---
updated-dependencies:
- dependency-name: golangci/golangci-lint-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/main.yml

@@ -64,7 +64,7 @@ jobs:
       # There is a risk of drift between the two, but this is only linting,
       # not runtime correctness!
       - name: golangci-lint
-        uses: golangci/golangci-lint-action@v5
+        uses: golangci/golangci-lint-action@v6
         with:
           working-directory: git-sync
           version: v1.53.3