fix: update GitHub Actions workflow to use supported runners

- Update runner from deprecated ubuntu-20.04 to ubuntu-latest
- Fix multi-line command syntax in test step
- Update GitHub Actions versions:
  - actions/checkout@v2 → @v4
  - actions/setup-go@v2 → @v5
  - tj-actions/verify-changed-files@v8.1 → @v20

This fixes the CI pipeline that was stuck waiting for runners.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: kalbhor

.github/workflows/test.yml

@@ -9,29 +9,30 @@ jobs:
       matrix:
         go: ["1.21"]
 
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
 
     name: Go ${{ matrix.go }} Tests
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
         with:
           persist-credentials: false # otherwise, the token used is the GITHUB_TOKEN, instead of your personal access token
 
       - name: Setup Go
-        uses: actions/setup-go@v2
+        uses: actions/setup-go@v5
         with:
           go-version: ${{ matrix.go }}
 
       - name: Verify dependencies
         run: go mod verify
 
       - name: Run Test
-        run: go test -v ./... -covermode=count -coverprofile=coverage.out
+        run: |
+          go test -v ./... -covermode=count -coverprofile=coverage.out
           go tool cover -func=coverage.out -o=coverage.out
 
       - name: Verify Changed files
-        uses: tj-actions/verify-changed-files@v8.1
+        uses: tj-actions/verify-changed-files@v20
         id: verify-changed-files
         with:
           files: README.md