Update CI Rubies

[st0012]

1. Since Ruby 3.2 has gone out for almost half of year, we should be able to use it for special suites like generating coverage or with --enable-frozen-string-literal falg
2. Given that we rarely adopt the latest Ruby features and Ruby has strong emphasise on backward-compatibility, I think testing against head just increases the chance of broken build unnecessarily. So I'm stopping testing against Ruby head now.

#skip-changelog

[codecov]

Codecov Report

Patch coverage: 85.71% and project coverage change: +4.58 🎉

Comparison is base (fea18fe) 78.62% compared to head (3c063a2) 83.20%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2052      +/-   ##
==========================================
+ Coverage   78.62%   83.20%   +4.58%     
==========================================
  Files         114      119       +5     
  Lines        5268     5651     +383     
==========================================
+ Hits         4142     4702     +560     
+ Misses       1126      949     -177     

Impacted Files	Coverage Δ
...entry-rails/lib/sentry/rails/capture_exceptions.rb	96.77% <85.71%> (-3.23%)	⬇️

... and 22 files with indirect coverage changes

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