Updates the build configuration to use a relative path when setting the :framework-api:javadoc tasks's overview property. This will help prevent a cache miss when a local build should have hit on a remote cache entry populated by a CI build, or in the case that the repository is relocated on disk. This cache miss adds around 46s of serial execution time to the build.

Tests

Running back to back builds with no changes from different file system locations... * task input comparison prior to this PR - although no changes were made between these builds, the :framework-api:javadoc task re-executed because of this input difference.

Using IntelliJ to compare the generated javadoc jar files, the javadoc jars produced before and after this change have the same contents.

Spring Use relative path for javadoc overview

Comment From: snicoll

Thanks very much @tylerbertrand