Revert "Test on Java LTS 14 and remove Java 15"
Revert "Test on Java LTS 14 and remove Java 15"

This reverts commit f7e34671c3d1a8b590b8ee8d0ff82b62579d80fa.

mirasrael/commons-csv,mirasrael/commons-csv,apache/commons-csv,apache/commons-csv