Fix scalafmt check

.github/workflows/run-ci.yml

@@ -29,6 +29,10 @@ jobs:
     name: Documentation and formatting
     runs-on: ubuntu-latest
     steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Setup Scala
+        uses: olafurpg/setup-scala@v10
       - name: Check Formatting
         run: sbt scalafmtCheckAll