Bump actions/cache from v2.1.4 to v2.1.5

Bumps [actions/cache](https://github.com/actions/cache) from v2.1.4 to v2.1.5.
- [Release notes](https://github.com/actions/cache/releases)
- [Commits](actions/cache@v2.1.4...1a9e213)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/haskell-ci.yml

@@ -119,7 +119,7 @@ jobs:
         run: |
           $CABAL v2-update -v
       - name: cache (tools)
-        uses: actions/[email protected].4
+        uses: actions/[email protected].5
         with:
           key: ${{ runner.os }}-${{ matrix.ghc }}-tools-2f29a7e3
           path: ~/.haskell-ci-tools
@@ -173,7 +173,7 @@ jobs:
           $CABAL v2-build $ARG_COMPILER $ARG_TESTS $ARG_BENCH --dry-run all
           cabal-plan
       - name: cache
-        uses: actions/[email protected].4
+        uses: actions/[email protected].5
         with:
           key: ${{ runner.os }}-${{ matrix.ghc }}-${{ github.sha }}
           path: ~/.cabal/store

.github/workflows/windows_and_macOS.yml

@@ -25,7 +25,7 @@ jobs:
         ghc-version: ${{ matrix.ghc }}
     - name: Update cabal package database
       run: cabal update
-    - uses: actions/[email protected].4
+    - uses: actions/[email protected].5
       name: Cache cabal stuff
       with:
         path: ${{ steps.setup-haskell-cabal.outputs.cabal-store }}