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/ci.yml

@@ -14,7 +14,7 @@ jobs:
       - uses: actions/setup-python@v2
       - uses: actions/checkout@v2
       - run: sudo apt install -y gettext aspell libenchant-dev
-      - uses: actions/cache@v2
+      - uses: actions/cache@v2.1.4
         with:
           path: ~/.cache/pip
           key: ${{ runner.os }}-pip-${{ hashFiles('**/requirements.txt') }}
@@ -37,7 +37,7 @@ jobs:
     steps:
       - uses: actions/setup-python@v2
       - uses: actions/checkout@v2
-      - uses: actions/cache@v2
+      - uses: actions/cache@v2.1.4
         with:
           path: ~/.cache/pip
           key: ${{ runner.os }}-pip-${{ hashFiles('**/requirements.txt') }}