Add CI workflow for running tests

Author: CDThomas

.github/workflows/test.yml

@@ -0,0 +1,22 @@
+name: "StashRB: Test"
+on:
+  pull_request:
+    branches: [ main ]
+  push:
+    branches: [ main ]
+jobs:
+  run-specs:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        ruby-version: [2.7, 3.0, 3.1]
+    env:
+      RSPEC_FULL_BACKTRACE: yes
+    steps:
+      - uses: actions/checkout@v2
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby-version }}
+          bundler-cache: true
+      - name: Run the tests
+        run: bundle exec rake test