Move to release candidate status

Author: JoaoRodrigues

setup.py

@@ -27,7 +27,7 @@
 
 setup(
     name='pdb-tools',  # Required
-    version='2.0.0-beta.7',  # Required
+    version='2.0.0-rc1',  # Required
     description='A swiss army knife for PDB files.',  # Optional
     long_description=long_description,  # Optional
     long_description_content_type='text/markdown',  # Optional (see note above)