cache ivy downloads

Author: dwickern

.github/workflows/build.yml

@@ -12,10 +12,21 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
-    - name: Set up JDK 1.8
-      uses: actions/setup-java@v1
-      with:
-        java-version: 1.8
-    - name: Run tests
-      run: sbt test
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Set up JDK 1.8
+        uses: actions/setup-java@v1
+        with:
+          java-version: 1.8
+
+      - name: Cache SBT
+        uses: actions/cache@v2
+        with:
+          path: |
+            ~/.ivy2/cache
+            ~/.sbt
+          key: ${{ runner.os }}-sbt-${{ hashFiles('**/build.sbt', '**/plugins.sbt') }}
+
+      - name: Run tests
+        run: sbt test