chore: use go-version-file instead of hard-coded Go version in GitHub Actions (#1353)

- Replace hard-coded go-version with go-version-file: 'go.mod' in all workflows
- Move checkout action before setup-go where needed for go-version-file to work
- Affects workflows: manual-releaser, release, run-tests, focused-test

Author: blgm

.github/workflows/focused-test.yml

@@ -6,9 +6,9 @@ jobs:
   focused-test:
     runs-on: ubuntu-latest
     steps:
+      - uses: actions/checkout@v6
       - uses: actions/setup-go@v6
         with:
-          go-version: '1.25.3'
-      - uses: actions/checkout@v6
+          go-version-file: 'go.mod'
       - run: go tool ginkgo unfocus && test -z "$(git status -s)"
 

.github/workflows/manual-releaser.yml

@@ -17,7 +17,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v6
         with:
-          go-version: '1.25.3'
+          go-version-file: 'go.mod'
       - name: Run GoReleaser
         uses: goreleaser/goreleaser-action@v6
         with:

.github/workflows/release.yml

@@ -16,7 +16,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v6
         with:
-          go-version: '1.25.3'
+          go-version-file: 'go.mod'
       - name: Run GoReleaser
         uses: goreleaser/goreleaser-action@v6
         with:

.github/workflows/run-tests.yml

@@ -17,10 +17,10 @@ jobs:
     outputs:
       pr_number: ${{ github.event.number }}
     steps:
+    - uses: actions/checkout@v6
     - uses: actions/setup-go@v6
       with:
-        go-version: '1.25.3'
-    - uses: actions/checkout@v6
+        go-version-file: 'go.mod'
     - run: make test
   call-dependabot-pr-workflow:
     needs: test