Remove Ruby 2.2 from CI because it's not supported by Ruby anymore and it breaks the CI

Author: ArturT

.github/workflows/ruby.yml

@@ -14,7 +14,7 @@ jobs:
       fail-fast: false
       matrix:
         # Due to https://github.com/actions/runner/issues/849, we have to use quotes for '3.0'
-        ruby: [2.2, 2.3, 2.4, 2.5, 2.6, 2.7, '3.0', 3.2, truffleruby-head]
+        ruby: [2.3, 2.4, 2.5, 2.6, 2.7, '3.0', 3.2, truffleruby-head]
 
     steps:
     - uses: actions/checkout@v2