Read version.txt when building the docs

docs/conf.py

@@ -31,6 +31,9 @@ for item in os.listdir(parent):
     if item.endswith('.egg'):
         sys.path.append(os.path.join(parent, item))
 
+version_txt = os.path.join(parent, 'supervisor/version.txt')
+supervisor_version = open(version_txt).read().strip()
+
 # General configuration
 # ---------------------
 
@@ -56,7 +59,7 @@ copyright = '2004-%d, Agendaless Consulting and Contributors' % year
 # other places throughout the built documents.
 #
 # The short X.Y version.
-version = '3.0a10'
+version = supervisor_version
 # The full version, including alpha/beta/rc tags.
 release = version