[ANN] wxRuby3 v1.8.1 released

[Martin Corino]

This is a maintenance release providing some minor bugfixes and improvements. Most importantly this release updates to target the latest wxWidgets 3.3.3 release.

What's Changed

• move CIRRUS CI builds to GitHub actions
• update for removal wxUSE_GEOMETRY in wxw >= 3.3.3
• update for wxSVGFileDC additions in wxw >= 3.3.3
• various other minor wxw >= 3.3.3 compatibility updates
• some small bug fixes
• update targeted wxWidgets release to 3.3.3

For more details see the original release announcement here: https://github.com/mcorino/wxRuby3/discussions/512