Version 2.2.0

* Fix `picobox.singleton`, `picobox.threadlocal` & `picobox.contextvars`
  scopes so they do not fail with unexpected exception when non-string
  formattable missing key is passed.

* Add `picobox.contrib.flaskscopes` module with *application* and *request*
  scopes for Flask web framework.

* Add `picobox.Stack` class to create stacks with boxes on demand. Might
  be useful for third-party developers who want to use picobox yet avoid
  collisions with main application developers.

docs/index.rst

@@ -333,7 +333,8 @@ Release Notes
     backward incompatible changes will be released along with bumping major
     version component.
 
-Not released changes.
+2.2.0
+`````
 
 * Fix ``picobox.singleton``, ``picobox.threadlocal`` & ``picobox.contextvars``
   scopes so they do not fail with unexpected exception when non-string