Speed up staticcheck times (#4059)

Use the right cache key and specify all go.sum files.

Author: jack-edmonds-dd

.github/workflows/reusable-go-test.yml

@@ -39,18 +39,20 @@ jobs:
         with:
           go-version: ${{ matrix.go-version }}
           cache: true
-          cache-dependency-path: tests/go.sum
+          cache-dependency-path: |
+            go.sum
+            tests/go.sum
       - name: Staticcheck (api module)
         uses: dominikh/staticcheck-action@v1
         with:
           checks: "-SA1009"
           working-directory: api
-          cache-key: ${{ matrix.go }}
+          cache-key: ${{ matrix.go-version }}
       - name: Staticcheck (tests module)
         uses: dominikh/staticcheck-action@v1
         with:
           checks: "inherit,-SA1019"
-          cache-key: ${{ matrix.go }}
+          cache-key: ${{ matrix.go-version }}
           working-directory: tests
   test:
     strategy: