Bump actions/setup-go from 5 to 6

Bumps [actions/setup-go](https://github.com/actions/setup-go) from 5 to 6.
- [Release notes](https://github.com/actions/setup-go/releases)
- [Commits](actions/setup-go@v5...v6)

---
updated-dependencies:
- dependency-name: actions/setup-go
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/publish-docker-tester.yml

@@ -119,7 +119,7 @@ jobs:
       - name: Wait for gRPC port
         run: timeout 15 bash -c 'until echo > /dev/tcp/localhost/1337 2>/dev/null; do sleep 1; done' 2>/dev/null
       - name: Setup Go Environment
-        uses: actions/setup-go@v5
+        uses: actions/setup-go@v6
         with:
           go-version-file: 'go/dpservice-go/go.mod'
       - name: Run dpservice-go tests