Set version to 0.4.2rc1 (0.4.2.M1 was invalid for pypi.org)

Author: JEnoch

setup.py

@@ -22,7 +22,7 @@ def read(fname):
 
 setup(
     name='eclipse-zenoh',
-    version='0.4.2.M1',
+    version='0.4.2rc1',
     packages=['zenoh', 'zenoh.net', 'zenoh.core'],
     author='ADLINK zenoh team',
     author_email='zenoh@adlink-labs.tech',