Add Ruby 3.2 & 3.3 to CI matrix

.github/workflows/ruby.yml

@@ -9,7 +9,7 @@ jobs:
     strategy:
       matrix:
         gemfile: [Gemfile, gemfiles/minimum_rubocop.gemfile]
-        ruby: ["2.7", "3.0", "3.1"]
+        ruby: ["2.7", "3.0", "3.1", "3.2", "3.3"]
 
     env:
       BUNDLE_GEMFILE: ${{ matrix.gemfile }}

.ruby-version

@@ -1 +1 @@
-3.1.2
+3.3.0

Gemfile

@@ -8,3 +8,9 @@ gem "diffy"
 gem "minitest"
 gem "pry-byebug"
 gem "rake"
+
+# Fixes the following warning on Ruby 3.3:
+#   base64 was loaded from the standard library, but will no longer be part of the default gems since Ruby 3.4.0.
+#   Add base64 to your Gemfile or gemspec. Also contact author of rubocop-1.53.0 to add base64 into its gemspec.
+# Check if this is still necessary when the minimum RuboCop version is increased.
+gem "base64"

Gemfile.lock

@@ -8,6 +8,7 @@ GEM
   remote: https://rubygems.org/
   specs:
     ast (2.4.2)
+    base64 (0.2.0)
     byebug (11.1.3)
     coderay (1.1.3)
     diffy (3.4.2)
@@ -50,6 +51,7 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
+  base64
   diffy
   minitest
   pry-byebug