Add some missing extensions to the README. (#2353)
treebc7ad670b11632c267b5dd47d392a3190698fc40
drwxr-xr-x - .github
-rw-r--r-- 307 .gitignore
drwxr-xr-x - .reuse
-rw-r--r-- 369 CODE_OF_CONDUCT.md
-rw-r--r-- 1724 CONTRIBUTING.adoc
-rw-r--r-- 3311 COPYING.adoc
-rw-r--r-- 1604 LICENSE.adoc
drwxr-xr-x - LICENSES
-rw-r--r-- 25174 README.md
drwxr-xr-x - extensions
drwxr-xr-x - specification