Re-introducing "v" prefix in version

Arnaud Breton · Arnaud Breton · commit 077acaad5046 · 2017-05-31T15:40:35.000+02:00
diff --git a/mailjet_rest/_version.py b/mailjet_rest/_version.py
@@ -1 +1 @@
-__version__ = "1.3.0"
+__version__ = "v1.3.0"
