rl 5.2.1, k 5.2.1

Merge pull request #142 from mn-io/java14-add-verbosity-to-actor2

add verbosity

rel 5.2 for all

Merge pull request #141 from mn-io/java14-fix-NPE-with-key

added tests

handle null keys

adaptions

Merge pull request #140 from mn-io/java14-more-type-information

replace capture in return types by object

ping returning Object instead of capture

add var args allMapped

bump versions

Merge remote-tracking branch 'origin/java14' into java14

make records jackson serializable