Bump actions/setup-go from 4 to 5

Bumps [actions/setup-go](https://github.com/actions/setup-go) from 4 to 5.
- [Release notes](https://github.com/actions/setup-go/releases)
- [Commits](actions/setup-go@v4...v5)

---
updated-dependencies:
- dependency-name: actions/setup-go
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/gateway-conformance.yml

@@ -12,7 +12,7 @@ jobs:
     steps:
       # 1. Start the Kubo gateway
       - name: Setup Go
-        uses: actions/setup-go@v4
+        uses: actions/setup-go@v5
         with:
           go-version: 1.21.x