Bump actions/cache from 2.1.5 to 2.1.6 (terraform-linters#118)

Bumps [actions/cache](https://github.com/actions/cache) from 2.1.5 to 2.1.6.
- [Release notes](https://github.com/actions/cache/releases)
- [Commits](actions/cache@v2.1.5...v2.1.6)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/build.yml

@@ -25,7 +25,7 @@ jobs:
       with:
         go-version: 1.16
     - name: Restore Cache
-      uses: actions/[email protected].5
+      uses: actions/[email protected].6
       with:
         path: |-
           ~/go/pkg/mod

.github/workflows/generated_code_checks.yml

@@ -15,7 +15,7 @@ jobs:
       with:
         go-version: 1.16
     - name: Restore Cache
-      uses: actions/[email protected].5
+      uses: actions/[email protected].6
       with:
         path: |-
           ~/go/pkg/mod

.github/workflows/release.yml

@@ -18,7 +18,7 @@ jobs:
       with:
         go-version: 1.16
     - name: Restore Cache
-      uses: actions/[email protected].5
+      uses: actions/[email protected].6
       with:
         path: |-
           ~/go/pkg/mod