dev: update cache key

Author: ernado

.github/workflows/pr.yml

@@ -43,9 +43,9 @@ jobs:
       - uses: actions/cache@v1
         with:
           path: ~/go/pkg/mod
-          key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
+          key: ${{ runner.os }}-go-${{ matrix.golang }}-${{ hashFiles('**/go.sum') }}
           restore-keys: |
-            ${{ runner.os }}-go-
+            ${{ runner.os }}-go-${{ matrix.golang }}-
       - name: Run tests on Unix-like operating systems
         run: make test
   check_generated: