Update to version 1.1.0: modernize codebase, and xcode.

[MikeWLloyd]

• Updated minimum supported macOS version to 11.0 (Big Sur+).
• Modernized Xcode build settings for current toolchains.
• Enabled hardened runtime and release-focused build optimizations.
• Added release automation for unsigned and signed build flows.

[matthewhively]

@MikeWLloyd maybe you should take a look at https://github.com/thealpa/SaneSideButtons/ (fork) instead?

[MikeWLloyd]

@matthewhively that’s fair, and I did’t realize the other fork was there. Thanks for the heads up! I did look, but I somehow missed it. This branch might still be useful to folks as the current 8 year old version still works without issue for me. Maybe others out there are in the same boat of wishing to continue to use this version, and avoid the ‘this application won’t be supported’ issue.