tests: use github.sha in binary cache key (#5062)

.github/workflows/tests.yml

@@ -45,11 +45,11 @@ jobs:
           restore-keys: |
             ${{ runner.os }}-go-
         if: "env.GIT_DIFF != ''"
-      # Cache bin
+      # Cache binaries for use by other jobs
       - uses: actions/cache@v1
         with:
           path: ~/go/bin
-          key: ${{ runner.os }}-${{ github.head_ref }}-tm-binary
+          key: ${{ runner.os }}-${{ github.sha }}-tm-binary
         if: "env.GIT_DIFF != ''"
 
   test_abci_apps:
@@ -79,7 +79,7 @@ jobs:
       - uses: actions/cache@v1
         with:
           path: ~/go/bin
-          key: ${{ runner.os }}-${{ github.head_ref }}-tm-binary
+          key: ${{ runner.os }}-${{ github.sha }}-tm-binary
         if: "env.GIT_DIFF != ''"
       - name: test_abci_apps
         run: abci/tests/test_app/test.sh
@@ -113,7 +113,7 @@ jobs:
       - uses: actions/cache@v1
         with:
           path: ~/go/bin
-          key: ${{ runner.os }}-${{ github.head_ref }}-tm-binary
+          key: ${{ runner.os }}-${{ github.sha }}-tm-binary
         if: "env.GIT_DIFF != ''"
       - run: abci/tests/test_cli/test.sh
         shell: bash
@@ -146,7 +146,7 @@ jobs:
       - uses: actions/cache@v1
         with:
           path: ~/go/bin
-          key: ${{ runner.os }}-${{ github.head_ref }}-tm-binary
+          key: ${{ runner.os }}-${{ github.sha }}-tm-binary
         if: "env.GIT_DIFF != ''"
       - name: test_apps
         run: test/app/test.sh