add setup-sbt action (scalapb#296)

Author: xuwei-k

.github/workflows/ci.yml

@@ -24,6 +24,8 @@ jobs:
           ~/.cache/coursier
         key: ${{ runner.os }}-sbt-${{matrix.scala}}-${{ hashFiles('**/*.sbt') }}
 
+    - uses: sbt/setup-sbt@v1
+
     - name: Formatting
       run: |
         sbt scalafmtCheck test:scalafmtCheck scalafmtSbtCheck

.github/workflows/release.yml

@@ -24,6 +24,7 @@ jobs:
         distribution: temurin
     - uses: olafurpg/setup-gpg@v3
       if: startsWith(github.ref, 'refs/tags/v')
+    - uses: sbt/setup-sbt@v1
     - name: Publish ${{ github.ref }}
       run: sbt ci-release
       env: