Bump actions/setup-go from 4 to 5 (#2913)

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

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/knative-dependabot.yaml

@@ -13,7 +13,7 @@ jobs:
     if: ${{ github.actor == 'dependabot[bot]' }}
     steps:
       - name: Set up Go 1.21.x
-        uses: actions/setup-go@v4
+        uses: actions/setup-go@v5
         with:
           go-version: 1.21.x
       - name: Checkout

.github/workflows/knative-downstream.yaml

@@ -50,7 +50,7 @@ jobs:
 
     steps:
     - name: Set up Go 1.21.x
-      uses: actions/setup-go@v4
+      uses: actions/setup-go@v5
       with:
         go-version: 1.21.x