Update sbt-assembly to 2.3.0 #985

Job	Run time
Docs	2m 38s
Compile and test (2.12.20, 8)	4m 13s
Checks	2m 25s
Compile Benchmarks	1m 24s
Gradle tests	3m 22s
Maven tests	2m 31s
Compile and test (2.12.20, 11)	4m 5s
sbt scripted tests (gen-scala-server, 2.12)	8m 48s
Compile and test (2.12.20, 17)	3m 53s
sbt scripted tests (gen-java, 2.12)	3m 54s
Compile and test (2.12.20, 21)	3m 38s
Compile and test (2.13.15, 8)	4m 44s
Compile and test (2.13.15, 11)	4m 45s
Compile and test (2.13.15, 17)	4m 24s
Compile and test (2.13.15, 21)	4m 6s
Compile and test (3.3.4, 8)	4m 40s
Compile and test (3.3.4, 11)	4m 42s
Compile and test (3.3.4, 17)	4m 44s
Compile and test (3.3.4, 21)	4m 10s
	1h 17m 6s

Provide feedback