feat(build): don't show prod warning in releases

The production warning is snown in all builds (dev and prod; weekly and rc) and in all versions expect prod builds of releases.

To iterate: only prod builds with versions matching /^v\d+\.\d+\.\d+$/ don't have the production warning.

Closes #11366

grunt/options/aliases.coffee

@@ -96,7 +96,7 @@ module.exports =
             'htmlmin'
             'htmllint'
             'useMinAssets'
-            #'imagemin'
+            'imagemin'
             'notify:min'
             'tarball'
             'nfp:dist'
@@ -199,5 +199,5 @@ module.exports =
     # 'INTERNAL: Removes a not for production warning from the distribution package.'
     'nfp:dist':
         [
-            'replace:nfpDist'
+            'nfp:release'
         ]

grunt/tasks/nfp.coffee

@@ -5,4 +5,14 @@ module.exports = (grunt)->
         'INTERNAL: Adds a production warning by creating an empty file with a corresponding name in the build folder.'
         ->
             grunt.file.write 'build/NOT_FOR_PRODUCTION', 'use dist \'folder\' instead'
+    )
+
+    grunt.registerTask(
+        'nfp:release'
+        'INTERNAL: Removes a production warning from a release build. It\' left in weekly and rc builds.'
+        ->
+            pkg = grunt.option 'pkg'
+
+            if pkg.core.version.match /^\d+\.\d+\.\d+$/
+                grunt.task.run 'replace:nfpDist'
     )