Bump actions/cache from 2.1.4 to 2.1.6

Bumps [actions/cache](https://github.com/actions/cache) from 2.1.4 to 2.1.6.
- [Release notes](https://github.com/actions/cache/releases)
- [Commits](actions/cache@v2.1.4...v2.1.6)

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

Author: dependabot[bot]

.github/workflows/push.yml

@@ -80,7 +80,7 @@ jobs:
           key: ${{ env.key }}
 
       - name: Cache extensions
-        uses: actions/[email protected].4
+        uses: actions/[email protected].6
         with:
           path: ${{ steps.cache-env.outputs.dir }}
           key: ${{ steps.cache-env.outputs.key }}
@@ -119,7 +119,7 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - name: Restore/cache vendor folder
-        uses: actions/[email protected].4
+        uses: actions/[email protected].6
         with:
           path: vendor
           key: all-build-${{ hashFiles('**/composer.lock') }}
@@ -178,7 +178,7 @@ jobs:
           key: ${{ env.key }}
 
       - name: Cache extensions
-        uses: actions/[email protected].4
+        uses: actions/[email protected].6
         with:
           path: ${{ steps.cache-env.outputs.dir }}
           key: ${{ steps.cache-env.outputs.key }}