Quote Ruby versions to avoid implicit Float conversions.

Author: postmodern

.github/workflows/ruby.yml

@@ -9,10 +9,10 @@ jobs:
       fail-fast: false
       matrix:
         ruby:
-          - 3.0
-          - 3.1
-          - 3.2
-          - 3.3
+          - '3.0'
+          - '3.1'
+          - '3.2'
+          - '3.3'
           - jruby
           - truffleruby
     name: OS ${{ matrix.os }} / Ruby ${{ matrix.ruby }}