Update galaxy.yml: Add empty dependencies to calm down ansible-agalxy command

dependencoies may not be an empty dict like in the past, but it may also not
be missing. It simply needs to be empty.

Fixes #146 (ansible-freeipa collection not installable by 2.9 ansible-galaxy collection install)

galaxy.yml

@@ -15,6 +15,8 @@ readme: "README.md"
 license: "GPL-3.0-or-later"
 license_file: "COPYING"
 
+dependencies:
+
 tags:
   - "identity"
   - "ipa"