📝 Add note about network filter

Author: davisshaver

readme.md

@@ -56,4 +56,6 @@ Find reference implementations of all filters in [example plugin here](https://g
 
 **`wp_rainbow_infura_id`** - Filter Infura ID to override settings value.
 
+**`wp_rainbow_infura_network`** - Filter Infura network to override settings value.
+
 **`wp_rainbow_redirect_url`** - Filter login redirect URL.