bumping ruby 3 to 3.0.6 to hopefully fix bundler issue

Author: tstannard

.github/workflows/ci.yml

@@ -10,7 +10,7 @@ jobs:
         ruby:
           # See comment comes from https://github.com/ruby/setup-ruby#matrix-of-ruby-versions
           # Due to https://github.com/actions/runner/issues/849, we have to use quotes for '3.0'
-          - '3.0'
+          - '3.0.6'
           - 3.1
           - 3.2
           - 3.3