Thirdparty licenses missing in core, Maven plugins version update

update required for below listed change 

1. [core] THIRD_PARTY_LICENSES.txt should be placed in root directory (inside jar)
2. [core] LICENSE.txt should be placed in root directory (inside jar)
3.  [core] update maven dependent plugin with latest version : 
   1. org.apache.maven.plugins:maven-jar-plugin:3.2.0 (old : 3.1.0)
   2. org.apache.maven.plugins:maven-resources-plugin:3.2.0 (old : 3.0.2) 
   3. org.apache.maven.plugins:maven-source-plugin:3.2.1 (old: 3.0.2) 
   4. org.apache.maven.plugins:maven-javadoc-plugin: 3.2.0 (old : 3.0.2) 
4. [jmc] 
   1. org.commonjava.maven.plugins:directory-maven-plugin:0.3.1 (old : 0.2)
   2. org.apache.maven.plugins:maven-resource-plugin:3.2.0 (old : 3.0.2)
5. junit:junit:4.13.1 (old : 4.12)