Add GitHub Actions workflow for testing

In addition to CircleCI.

.github/workflows/test.yml

@@ -0,0 +1,22 @@
+name: Clojure CI
+
+on: [push]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        java: [ '8', '11' ]
+    steps:
+      - uses: actions/checkout@v1
+      - name: Setup Java
+        uses: actions/setup-java@v1
+        with:
+          java-version: ${{ matrix.java }}
+      - name: Setup Clojure
+        uses: DeLaGuardo/setup-clojure@1.0
+        with:
+          tools-deps: '1.10.1.469'
+      - name: Run Tests
+        run: clojure -A:test:runner