Quote ruby version numbers to prevent them from being parsed as floats.

postmodern · postmodern · commit 0914fad1f86a · 2023-12-27T20:56:29.000-08:00
diff --git a/.github/workflows/ruby.yml b/.github/workflows/ruby.yml
@@ -10,8 +10,8 @@ jobs:
       matrix:
         ruby:
           - '3.0'
-          - 3.1
-          - 3.2
+          - '3.1'
+          - '3.2'
           - jruby
           - truffleruby-head
     name: Ruby ${{ matrix.ruby }}
