Cache cleanup does not clean cache entries for newly released Gradle versions

[bigdaz]

Gradle User Home cache cleanup requires Gradle 8.11 to execute.

• If a version >= 8.11 is found on the PATH, then this version is used for cache-cleanup.
• If no version is found on PATH (or an older version) then 8.11 will be downloaded and used.

If a Gradle Wrapper build runs with a newer version of Gradle (eg Gradle 8.11.1), then it will generate Gradle User Home content that will not be removed by cache cleanup running with Gradle 8.11.
For example, transform outputs are stored under ~/.gradle/caches/<gradle-version>/transforms, and caches/8.12/transforms will not be removed by cache-cleanup running with Gradle 8.11. This can result in ever-growing cache entry sizes.

To workaround this issue, ensure that there is a version of Gradle available on the PATH, and that this version is at least as new as any version used to run Gradle Wrapper builds.

uses: gradle/actions/setup-gradle@v4
with:
  gradle-version: "8.11.1" # Set to the newest version of Gradle used to build

Fixing this (without reverting to the old behaviour of always installing the latest Gradle) will involve detecting the newest Gradle version executed for a Job, and ensuring that cleanup is executed with at least that Gradle version.