Omit project version from docs

This is more maintainable while the project simply posts the latest docs
from master.

[skip ci]

Author: aantron

docs/conf.py

@@ -61,9 +61,9 @@
 # built documents.
 #
 # The short X.Y version.
-version = '0.5.0'
+# version = '0.5.0'
 # The full version, including alpha/beta/rc tags.
-release = '0.5.0'
+# release = '0.5.0'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.