add gh requirement to readme (#56)

Author: maltesander

release/README.adoc

@@ -43,7 +43,11 @@ cargo install cargo-edit --version 0.11.11
 
 ### yq (yaml parser)
 
-This script requires https://github.com/mikefarah/yq (not to be confused with https://github.com/kislyuk/yq)
+This script requires https://github.com/mikefarah/yq (not to be confused with https://github.com/kislyuk/yq).
+
+### gh (github client)
+
+This script requires https://github.com/cli to be installed.
 
 ## Usage