feat: add support for macOS Apple Silicon (aarch64)

[sk8erboi17]

This PR enables support for Apple Silicon and updates the build configuration for Java 21.

Changes:

• SCSSCompiler.java: Updated platform detection to handle macos-aarch64.
• pom.xml (Parent): Upgraded Maven plugins (compiler, javadoc, surefire, etc.)
• .gitignore: Added .idea/ to prevent tracking of local IDE settings.

[hjohn]

What was the problem you encountered? It should already work for macos-arm64 ; your fix changes the platform names, but if you do that, they won't match the SCSS binary files included with this project.

[sk8erboi17]

You're right, I see the naming mismatch now. The IllegalStateException I encountered was specifically for mac-aarch64. This happened because Java reports aarch64, but the binaries use the macos-arm64 naming convention you mentioned.

The project was throwing java.lang.IllegalStateException: Unsupported platform: mac-aarch64 on Apple Silicon because the aarch64 architecture was not being correctly mapped to the internal resources.

This is what your string platform returns:

I've reverted the changes to the Java source code. Instead, I handled the fix entirely within the pom.xml by aligning the resource filenames with the existing platform detection logic.

[hjohn]

Thanks, if you could remove the snapshot change, I'll integrate it (the version is set automatically by the release process, no need to change pom versions).

[sk8erboi17]

Done!

[hjohn]

Looks good, thanks very much!