Migrate benchmarks from Scala 2.12 to Scala 2.13/3.x

[farquet]

Opening to keep track of benchmarks still stuck on Scala 2.12.

As of Spark 3.2.0, Scala 2.13 is now supported: https://spark.apache.org/releases/spark-release-3-2-0.html

Should be eventually migrated away from 2.12 (to 2.13/3.x):

• apache-spark benchmarks (Update apache-spark benchmarks to use Spark 3.2.0 and Scala 2.13.7 #327)
• reactors
• neo4j-analytics (Update Neo4j to version 5.12.0 and migrate to Scala 2.13 #422)
• scala-stm-bench7 and philosophers (Migrate scala-stm benchmarks from Scala 2.12 to Scala 3 #445)
• finagle-http and finagle-chirper (Update twitter-finagle benchmarks to use Finagle 21.10.0 and Scala 2.13.7 #328)

[lbulej]

With neo4j-analytics, the problem is the Cypher component of Neo4j (neo4j/neo4j#12687) that keeps it chained to Scala 2.12.

[lbulej]

With neo4j-analytics done (#422), we have just 3 benchmarks (in 2 modules) left.