Include web portal version in oauth client registration

This could be shown in client listings and audit logs, and checked to
ensure old versions stop being used. Not the most relevant for the web
portal as it is closely tied together with the server, but could help
answer questions about where old grants come from.

snikket_web/prosodyclient.py

@@ -29,7 +29,7 @@ from flask import g as _app_ctx_stack
 
 import werkzeug.exceptions
 
-from . import xmpputil
+from . import xmpputil, _version
 from .xmpputil import split_jid
 
 
@@ -474,6 +474,7 @@ class ProsodyClient:
             ],
             "grant_types": ["password"],
             "response_types": ["code"],
+            "software_version": _version.version,
         }
         async with self._plain_session as session:
             async with session.post(