Add cherry_picker to CODEOWNERS (#256)

Author: Mariatta

.github/CODEOWNERS

@@ -0,0 +1,8 @@
+# See https://help.github.com/articles/about-codeowners/
+# for more info about CODEOWNERS file
+
+# It uses the same pattern rule for gitignore file
+# https://git-scm.com/docs/gitignore#_pattern_format
+
+# cherry_picker
+**/*cherry_picker*                  @Mariatta