Test sbt-dotty on sbt 1.5

Author: adpi2

.github/workflows/ci.yaml

@@ -282,9 +282,12 @@ jobs:
       - name: Add SBT proxy repositories
         run: cp -vf .github/workflows/repositories /root/.sbt/ ; true
 
-      - name: Test
+      - name: Test sbt 1.4.x
         run: ./project/scripts/sbt "sbt-dotty/scripted; sbt-community-build/scripted"
 
+      - name: Test sbt 1.5.x
+        run: ./project/scripts/sbt "set \`sbt-dotty\`/scriptedSbt := \"1.5.0-RC1\"; sbt-dotty/scripted sbt-dotty/*"
+
   test_java8:
     runs-on: [self-hosted, Linux]
     container: