fix: add new line after facebook proguard rules in android builds

If facebook is used and also google play, then the proguard rules may be corrupted because of the missing new line after the facebook rules.

maven/codenameone-maven-plugin/src/main/java/com/codename1/builders/AndroidGradleBuilder.java

@@ -1033,7 +1033,7 @@ public boolean build(File sourceZip, final BuildRequest request) throws BuildExc
                     + "-keepattributes Signature\n"
                     + "-dontwarn bolts.**\n"
                     + "-dontnote android.support.**\n"
-                    + "-dontnote androidx.**";
+                    + "-dontnote androidx.**\n";
 
 
             facebookActivityMetaData = " <meta-data android:name=\"com.facebook.sdk.ApplicationId\" android:value=\"@string/facebook_app_id\"/>\n";