Release MapLibre Android

We make MapLibre Android releases as a downloadable asset on GitHub as well as to Maven Central.

Also see the current release policy.

Making a release

To make an Android release, do the following:

Prepare a PR.
- Update CHANGELOG.md in a PR, see for example this PR. The changelog should contain links to all relevant PRs for Android since the last release. You can use the script below with a GitHub access token with the public_repo scope. You will need to filter out PRs that do not relate to Android and categorize PRs as features or bugfixes.
```
GITHUB_ACCESS_TOKEN=... node scripts/generate-changelog.mjs android
```
  The heading in the changelog must match ## <VERSION> exactly, or it will not be picked up. For example, for version 9.6.0:
```
## 9.6.0
```
- Update android/VERSION with the new version.
Once the PR is merged, the android-release.yml workflow will run automatically to make the release. It builds every published build flavor as a release and a debug build, and signs the publications of each with the publish<Variant>Publications Gradle task (e.g. publishOpenglWithPluginApiReleasePublications). Each build uploads its publications to Maven Central as a deployment, which Maven Central validates but does not publish yet. Only when all builds have succeeded does the workflow publish all deployments. Deployments of a release that is abandoned after a failure can be dropped in the Central Portal.