Added claim grant_types as supported by client.

Author: rohe

src/idpyoidc/__init__.py

@@ -10,7 +10,7 @@ def verified_claim_name(claim):
 
 def proper_path(path):
     """
-    Clean up the path specification so it looks like something I could use.
+    Clean up the path specification such that it looks like something I could use.
     "./" <path> "/"
     """
     if path.startswith("./"):

src/idpyoidc/client/oauth2/authorization.py

@@ -32,6 +32,7 @@ class Authorization(Service):
     _supports = {
         "response_types_supported": ["code"],
         "response_modes_supported": ["query", "fragment"],
+        "grant_types": []
     }
 
     _callback_path = {

src/idpyoidc/server/oauth2/authorization.py

@@ -359,6 +359,7 @@ class Authorization(Endpoint):
         # "grant_types_supported": ["authorization_code", "implicit"],
         "code_challenge_methods_supported": ["S256"],
         "scopes_supported": [],
+        # "grant_types": [],
     }
     default_capabilities = {
         "client_authn_method": ["request_param", "public"],