Bump actions/cache from 2.1.5 to 2.1.7 (#784)

Bumps [actions/cache](https://github.com/actions/cache) from 2.1.5 to 2.1.7.
- [Release notes](https://github.com/actions/cache/releases)
- [Commits](actions/cache@v2.1.5...v2.1.7)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

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

.github/workflows/test-library.yml

@@ -131,7 +131,7 @@ jobs:
     - name: Set up pip cache
       if: >-
         steps.request-check.outputs.release-requested != 'true'
-      uses: actions/[email protected].5
+      uses: actions/[email protected].7
       with:
         path: ${{ steps.pip-cache-dir.outputs.dir }}
         key: >-
@@ -228,7 +228,7 @@ jobs:
       run: >-
         echo "::set-output name=dir::$(pip cache dir)"
     - name: Set up pip cache
-      uses: actions/[email protected].5
+      uses: actions/[email protected].7
       with:
         path: ${{ steps.pip-cache.outputs.dir }}
         key: >-
@@ -349,7 +349,7 @@ jobs:
       run: >-
         echo "::set-output name=dir::$(pip cache dir)"
     - name: Set up pip cache
-      uses: actions/[email protected].5
+      uses: actions/[email protected].7
       with:
         path: ${{ steps.pip-cache.outputs.dir }}
         key: >-
@@ -464,7 +464,7 @@ jobs:
       run: >-
         echo "::set-output name=dir::$(pip cache dir)"
     - name: Set up pip cache
-      uses: actions/[email protected].5
+      uses: actions/[email protected].7
       with:
         path: ${{ steps.pip-cache.outputs.dir }}
         key: >-