Update buildkite pipeline to run tests using Ruby 2.7.4 and 3.2.2

.buildkite/pipeline.yml

@@ -1,7 +1,7 @@
 # Nodes with values to reuse in the pipeline.
 common_params:
   env: &xcode_image
-    IMAGE_ID: xcode-14.1
+    IMAGE_ID: xcode-14.3.1
   plugins:
   - &docker_plugin
     docker#v3.8.0:
@@ -21,9 +21,14 @@ steps:
   #################
   # Build and Test
   #################
-  - label: "🧪 Build and Test"
+  - label: "🧪 Build and Test using Ruby {{ matrix.ruby }}"
     key: test
     command: |
+      echo "--- :ruby: Using ruby {{ matrix.ruby }}"
+      export RBENV_VERSION={{ matrix.ruby }}
+      ruby --version
+
+      echo "--- :package: Installing homebrew packages"
       # We only need this for tasks running on a Mac
       brew install pkg-config git-lfs libxml2 imagemagick@6
 
@@ -42,6 +47,11 @@ steps:
       - automattic/a8c-ci-toolkit#2.15.0
     agents:
       queue: "mac"
+    matrix:
+      setup:
+        ruby:
+          - 2.7.4
+          - 3.2.2
 
   #################
   # Lint
@@ -79,7 +89,7 @@ steps:
      - test
      - rubocop
      - danger
-    # Note: We intentionally call a separate `.sh` script here (as opposed to having all the 
+    # Note: We intentionally call a separate `.sh` script here (as opposed to having all the
     # commands written inline) to avoid leaking a key used in the process in clear in the
     # BUILDKITE_COMMAND environment variable.
     command: .buildkite/gem-push.sh