update release instructions

Author: kwin

com.googlecode.cppcheclipse.parent/release.txt

@@ -1,7 +1,10 @@
 To release version x do the following steps:
 
+make sure there are no uncommitted changes
 mvn -Dtycho.mode=maven org.eclipse.tycho:tycho-versions-plugin:set-version -DnewVersion=<version x>
 build
 copy to p2 update site
-tag
-mvn -Dtycho.mode=maven org.eclipse.tycho:tycho-versions-plugin:set-version -DnewVersion=<version x+1>-SNAPSHOT
+tag (from local workspace)
+mvn -Dtycho.mode=maven org.eclipse.tycho:tycho-versions-plugin:set-version -DnewVersion=<version x+1>-SNAPSHOT
+afterwards the category.xml has to be updated manually, due to the changed version of the referenced feature
+commit