Bump actions/cache from 3.2.5 to 3.2.6 (#3349)

Bumps [actions/cache](https://github.com/actions/cache) from 3.2.5 to 3.2.6.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@6998d13...69d9d44)

---
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>

Author: dependabot[bot]

.github/workflows/test.yaml

@@ -46,7 +46,7 @@ jobs:
         run: echo "::set-output name=today::$(date +'%Y-%m-%d')"
         shell: bash
       - name: Cache clean flutter
-        uses: actions/cache@6998d139ddd3e68c71e9e398d8e40b71a2f39812
+        uses: actions/cache@69d9d449aced6a2ede0bc19182fadc3a0a42d2b0
         if: matrix.job == 'flutter'
         env:
           # Increment version to invalidate bad/obsolete caches.
@@ -55,7 +55,7 @@ jobs:
           path: ~/.dartdoc_grinder
           key: ${{ runner.os }}-test-${{ env.cache-name }}-${{ steps.date.outputs.today }}
       - name: Cache .pub-cache
-        uses: actions/cache@6998d139ddd3e68c71e9e398d8e40b71a2f39812
+        uses: actions/cache@69d9d449aced6a2ede0bc19182fadc3a0a42d2b0
         if: matrix.job == 'flutter'
         env:
           # Increment version to invalidate bad/obsolete caches.