mention lrclib in readme

Author: sentriz

config.example

@@ -66,6 +66,6 @@
 # addons add external metadata to tracks after a musicbrainz match. can be used when importing for web, sync cli, or normal cli.
 # addons can have have arguments too. for example "addon replaygain true-peak" or "addon replaygain force".
 
-#addon lyrics genius musixmatch
+#addon lyrics lrclib genius musixmatch
 #addon replaygain
 #addon subproc my-command args <files>