debug: add timeout to test job and include debug step for failure cases

Author: YukiTsuchida

.github/workflows/test.yml

@@ -5,6 +5,7 @@ jobs:
   test:
     name: Test
     runs-on: ubuntu-latest
+    timeout-minutes: 120
     steps:
 
     - name: Set up Go 1.16
@@ -31,3 +32,7 @@ jobs:
 
     - name: Test
       run: make test
+
+    - name: Debug with tmate (open shell)
+      if: ${{ failure() }}
+      uses: mxschmitt/action-tmate@v3