(PA-5641) Update rspec tests with modern Ruby

This commit updates the versions of Ruby and Puppet that rspec tests run
on to include Ruby 3.2 and Puppet 8.

.github/workflows/rspec_tests.yaml

@@ -11,23 +11,25 @@ permissions:
 
 jobs:
   rspec_tests:
-    name: RSpec (Ruby ${{ matrix.ruby }}, Puppet ${{ matrix.puppet_version }})
+    name: RSpec (Ruby ${{ matrix.cfg.ruby }}, Puppet ${{ matrix.cfg.puppet_version }})
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby: [ '2.5', '2.7', 'jruby-9.2.17.0' ]
-        puppet_version: [ '~> 6.29', '~> 7.22' ]
+        cfg:
+          - {puppet_version: '7', ruby: '2.7'}
+          - {puppet_version: '7', ruby: 'jruby-9.3.7.0'}
+          - {puppet_version: '8', ruby: '3.2'}
     env:
-      PUPPET_GEM_VERSION: ${{ matrix.puppet_version }}
+      PUPPET_GEM_VERSION: ~> ${{ matrix.cfg.puppet_version }}
     steps:
       - name: Checkout current PR
         uses: actions/checkout@v3
         with:
           fetch-depth: 0
-      - name: Install Ruby version ${{ matrix.ruby }}
+      - name: Install Ruby version ${{ matrix.cfg.ruby }}
         uses: ruby/setup-ruby@v1
         with:
-          ruby-version: ${{ matrix.ruby }}
+          ruby-version: ${{ matrix.cfg.ruby }}
       - name: Update rubygems and install gems
         run: |
           gem update --system 3.3.26 --silent --no-document