Bump gradle from 3.6.2 to 7.0.1 in /SafDemos
Bump gradle from 3.6.2 to 7.0.1 in /SafDemos

Bumps gradle from 3.6.2 to 7.0.1.

---
updated-dependencies:
- dependency-name: com.android.tools.build:gradle
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>
android/storage-samples,android/storage-samples,android/storage-samples