Build and test Pekko with Scala 3 #405

Job	Run time
Test (testkit/test actor-tests/test)	6m 30s
Test (actor-testkit-typed/test actor-typed-tests/test)	6m 37s
Test (bench-jmh/test)	4m 36s
Test (cluster/test cluster-tools/test cluster-typed/test distributed-data/test cluster-metrics/te...	18m 25s
Test (discovery/test coordination/test)	3m 10s
Test (persistence/test persistence-shared/test persistence-query/test persistence-typed/test pers...	10m 26s
Test (pki/test slf4j/test)	2m 18s
Test (serialization-jackson/test)	3m 38s
Test (stream/test stream-testkit/test stream-tests/test stream-typed/test stream-typed-tests/test)	17m 10s
Test (stream-tests-tck/test)	5m 39s
Test (remote/test remote-tests/test protobuf-v3/test)	11m 3s
	1h 29m 32s

Provide feedback