devel/mill: Update to 0.10.3

• Fixed import $file for files with hyphens and other symbols in its name
• Fixed an issues with truncated output just before Mill finishes
• Mill commands now support arguments of type Task[T], which can improve writing re-usable commands, especially, they can be called from othe tasks more easily
• JavaModule: Improved correctness and performance of compileClasspath and bspCompileClasspath targets. This fixes an issue with BSP for large projects. Also, compile-time dependencies no longer sneak into the classpath transitively.
• JavaModule: Added docJarUseArgsFile target and fix issue with Windows command length restrictions in docJar
• BSP and Bloop: Better detect foreign modules
• Various internal API refinements and improvements
• Reorganized integration test suite and build setup

PR: 263314