Use better dev version number in docs

Author: Conengmo

docs/conf.py

@@ -10,6 +10,7 @@
 # serve to show the default.
 
 import os
+import subprocess
 import sys
 
 # Use the currently checked out folium of this folder
@@ -54,15 +55,10 @@
 # |version| and |release|, also used in various other places throughout the
 # built documents.
 
-# The full version, including alpha/beta/rc tags.
-
-import folium
-
-version = release = folium.__version__
-if "+" in version:
-    version, remainder = release.split("+")
-    if not remainder.startswith("0"):
-        version = version + ".dev+" + remainder.split(".")[0]
+version = subprocess.check_output(["git", "describe", "--tags"]).decode().strip()
+if "-" in version:
+    version.replace("-", ".dev", 1)
+release = version
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.