Add icon criteria to plugin docs quality list

Plugin-Certification-Program.md

@@ -84,6 +84,11 @@ Every certified plugin's documentation and release notes must meet minimum crite
   - Brief installation instructions which do not assume deep user familiarity with plugins generally, and which when followed exactly on a fresh installation of NetBox will result in a functioning plugin.
   - A summary of where and how to engage with the plugin's maintainer team for bug reports, feature requests, and documentation requests (GitHub issues, Slack, etc.)
   - A summary of where and how to seek support as a user of the plugin (GitHub discussions, Slack, etc.)
+  - An icon which:
+    - Has a square aspect ratio
+    - Scales recognizably at sizes from 48x48px through 500x500px
+    - Is licensed under a Creative Commons license that does not prohibit commercial use
+    - Is provided as either SVG or PNG with transparency
 - The plugin's main documentation must treat each of the points in the README in further depth. To minimize redundancy, linking into the main documentation from the top-level README is encouraged, particularly concerning the concise introduction.
 - Plugin documentation may _not_ consist solely of a top-level README unless the plugin's scope is exceptionally small.
 - Plugin's release notes must open with a brief narrative summary characterizing it as a major, minor, or patch release and indicating whether it consists of bug fixes, new features, enhancements to existing features, or all of the above.
@@ -116,4 +121,4 @@ If your plugin isn't ready for certification but you would like to see it listed
 - The best email address to reach you about the plugin in question
 - A link to the plugin's source repo
 - A link to the plugin's PyPI package entry
-- The plugin's config name (the value you add to `PLUGINS = []` in `configuration.py` when installing)
+- The plugin's config name (the value you add to `PLUGINS = []` in `configuration.py` when installing)