Updated change log

Author: kmvanbrunt

CHANGELOG.md

@@ -19,10 +19,13 @@
      scroll the actual error message off the screen.
     * Exceptions occurring in tab completion functions are now printed to stderr before returning control back to
     readline. This makes debugging a lot easier since readline suppresses these exceptions.
+    * Added support for custom Namespaces in the argparse decorators. See description of `ns_provider` argument
+    for more information.
 * Potentially breaking changes
     * Replaced `unquote_redirection_tokens()` with `unquote_specific_tokens()`. This was to support the fix
       that allows terminators in alias and macro values.
-    * Changed `Statement.pipe_to` to a string instead of a list 
+    * Changed `Statement.pipe_to` to a string instead of a list
+    * `preserve_quotes` is now a keyword-only argument in the argparse decorators
 * **Python 3.4 EOL notice**
     * Python 3.4 reached its [end of life](https://www.python.org/dev/peps/pep-0429/) on March 18, 2019
     * This is the last release of `cmd2` which will support Python 3.4