upgrade config to zola 0.19

Author: sirodoht

config.toml

@@ -11,14 +11,11 @@ compile_sass = false
 build_search_index = false
 
 # Generate RSS feed
-generate_feed = true
-feed_filename = "rss.xml"
-
-external_links_target_blank = true
+generate_feeds = true
+feed_filenames = ["rss.xml"]
 
 [markdown]
-# Whether to do syntax highlighting
-# Theme can be customised by setting the `highlight_theme` variable to a theme supported by Zola
+external_links_target_blank = true
 highlight_code = false
 
 [extra]