Make sure coursier install sbt on the CI

Author: Gedochao

.github/workflows/ci.yml

@@ -22,7 +22,7 @@ jobs:
       - uses: coursier/setup-action@v1
         with:
           jvm: ${{ matrix.jdk }}
-          apps: sbtn
+          apps: sbtn sbt
       - name: Set up Python ${{ matrix.python }}
         uses: actions/setup-python@v2
         with: