RAT check readme updated (#12170)

tests/nightly/apache_rat_license_check/README.md

@@ -14,7 +14,7 @@ The following commands can be used to run a Apache RAT check locally -
 
 Docker based 1-click-method:
 ```
-ci/build.py --platform ubuntu_rat /work/runtime_functions.sh nightly_test_rat_check
+ci/build.py -p ubuntu_rat nightly_test_rat_check
 ```
 
 Manual method:
@@ -25,8 +25,8 @@ sudo apt-get install maven -y #>/dev/null
 #install svn
 sudo apt-get install subversion -y #>/dev/null
 
-#download RAT
-svn co http://svn.apache.org/repos/asf/creadur/rat/trunk/ #>/dev/null
+#download RAT 0.12 version
+svn co http://svn.apache.org/repos/asf/creadur/rat/tags/apache-rat-project-0.12-RC3/ #>/dev/null
 
 #cd into correct directory
 cd trunk
@@ -38,5 +38,5 @@ mvn install #>/dev/null
 cd apache-rat/target
 
 #run Apache RAT check on the src
-java -jar apache-rat-0.13-SNAPSHOT.jar -E <path-to-.rat-excludes-file> -d <path-to-mxnet-source>
+java -jar apache-rat-0.12.jar -E <path-to-.rat-excludes-file> -d <path-to-mxnet-source>
 ```