Bump actions/cache from v2 to v2.1.4

Bumps [actions/cache](https://github.com/actions/cache) from v2 to v2.1.4.
- [Release notes](https://github.com/actions/cache/releases)
- [Commits](actions/cache@v2...26968a0)

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/pr.yml

@@ -71,7 +71,7 @@ jobs:
         uses: actions/setup-go@v2
         with:
           go-version: ${{ matrix.golang }}
-      - uses: actions/cache@v2
+      - uses: actions/cache@v2.1.4
         with:
           path: ~/go/pkg/mod
           key: ${{ runner.os }}-go-${{ matrix.golang }}-${{ hashFiles('**/go.sum') }}
@@ -91,7 +91,7 @@ jobs:
         uses: actions/setup-go@v2
         with:
           go-version: ${{ matrix.golang }}
-      - uses: actions/cache@v2
+      - uses: actions/cache@v2.1.4
         with:
           path: ~/go/pkg/mod
           key: ${{ runner.os }}-go-${{ matrix.golang }}-${{ hashFiles('**/go.sum') }}
@@ -125,7 +125,7 @@ jobs:
         uses: actions/setup-go@v2
         with:
           go-version: ${{ matrix.golang }}
-      - uses: actions/cache@v2
+      - uses: actions/cache@v2.1.4
         with:
           path: ~/go/pkg/mod
           key: coverage-${{ runner.os }}-go-${{ matrix.golang }}-${{ hashFiles('**/go.sum') }}