Set up sbt explicitly because it will be dropped in ubuntu-24.04 (#511)

See also: actions/runner-images#10636

.github/workflows/build-all-samples.yml

@@ -18,6 +18,7 @@ jobs:
         with:
           java-version: 21
           distribution: temurin
+      - uses: sbt/setup-sbt@v1
       - name: 'Build all samples using JShell'
         run: java src/Builder.java
       - name: 'Check automation for updating versions'