Issue 4516: Enforce copyright through Checkstyle (#4517)
Issue 4516: Enforce copyright through Checkstyle (#4517)

Changes the checkstyle configuration to validate the copyright statement in license headers.

Signed-off-by: Flavio Junqueira (fpj) <3143f522c4835f95078812226e7dab45695d0369@apache.org>


pravega/pravega,pravega/pravega,pravega/pravega