chore: bump proguard-gradle from 7.2.2 to 7.3.0 (#279)

Bumps [proguard-gradle](https://github.com/Guardsquare/proguard) from 7.2.2 to 7.3.0.
- [Release notes](https://github.com/Guardsquare/proguard/releases)
- [Commits](Guardsquare/proguard@v7.2.2...v7.3.0)

---
updated-dependencies:
- dependency-name: com.guardsquare:proguard-gradle
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

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

Author: dependabot[bot]