Bump plugin version to 4.0.0

Author: ryanberckmans

pretix_eth/__init__.py

@@ -1 +1 @@
-__version__ = "3.0.0-dev"
+__version__ = "4.0.0"

setup.py

@@ -44,7 +44,7 @@ def run(self):
 
 setup(
     name='pretix-eth-payment-plugin',
-    version='3.0.0-dev',
+    version='4.0.0',
     description='Ethereum payment provider plugin for pretix software',
     long_description=long_description,
     long_description_content_type='text/markdown',