Fix version in docs

Copied from MongoEngine

Author: lafrech

docs/conf.py

@@ -47,10 +47,11 @@
 # |version| and |release|, also used in various other places throughout the
 # built documents.
 #
+import flask_mongoengine
 # The short X.Y version.
-version = '0.1'
+version = flask_mongoengine.get_version()
 # The full version, including alpha/beta/rc tags.
-release = '0.1'
+release = flask_mongoengine.get_version()
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.