Bump actions/cache from v2.1.3 to v2.1.4

Bumps [actions/cache](https://github.com/actions/cache) from v2.1.3 to v2.1.4.
- [Release notes](https://github.com/actions/cache/releases)
- [Commits](actions/cache@v2.1.3...26968a0)

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

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -48,7 +48,7 @@ jobs:
           linker = "arm-linux-gnueabihf-gcc"
           EOF
       - name: Cache cargo
-        uses: actions/[email protected].3
+        uses: actions/[email protected].4
         id: cache
         with:
           path: ~/.cargo
@@ -90,7 +90,7 @@ jobs:
       - name: Ready cache
         run: sudo chown -R $(whoami):$(id -ng) ~/.cargo/
       - name: Cache cargo
-        uses: actions/[email protected].3
+        uses: actions/[email protected].4
         id: cache
         with:
           path: ~/.cargo