Should bump min Ruby version to 3.2

gruf-sentry uses def method(&) ... syntax which is only available since Ruby 3.1. But gruf-sentry.gemspec specifies Ruby 3.0 as min allowed version. You should set min allowed Ruby version to 3.1.

PS. We run out test suite against different Ruby versions and found that it fails on Ruby 3.0 + gruf-sentry 1.6.0 due to this bug.

UPD. I see that changelog for 1.6.0 include "Drop support for Ruby 3.0, 3.1". So, min Ruby version must be updated to 3.2 actually.