docs: add OpenSSF Best Practices registration badge

Author: hyperpolymath

README.adoc

@@ -4,6 +4,8 @@
 image:https://img.shields.io/badge/License-MPL--2.0-blue.svg[License: MPL-2.0,link="https://www.mozilla.org/en-US/MPL/2.0/"]
 
 = Gitbot Fleet
+image:https://img.shields.io/badge/OpenSSF-Best_Practices-green?logo=openssourcesecurity[OpenSSF Best Practices,link="https://www.bestpractices.dev/en/projects/new?repo_url=https://github.com/hyperpolymath/gitbot-fleet"]
+
 :toc: macro
 :toclevels: 2
 :icons: font