Update feed url for Grzegorz Śliwinki's blog (#593)

Author: fizyk

config/config.ini

@@ -513,7 +513,7 @@ name = Greg Taylor
 [http://agiletesting.blogspot.com/feeds/posts/default/-/python]
 name = Grig Gheorghiu
 
-[http://blog.fizyk.net.pl/tags/python.xml]
+[https://fizyk.dev/tags/python.xml]
 name = Grzegorz Śliwiński
 
 [http://neopythonic.blogspot.com/feeds/posts/default]