chore: add 3.5.0 schema (note: differs from 3.4.6)

However there are no changes to the generated code after running make
client, likely because we already included 3.6

Author: james-garner-canonical

juju/client/SCHEMAS.md

@@ -32,3 +32,6 @@ Please see docs/CONTRIBUTING.md for the process for updating this file.
 3.4.4 (identical to 3.4.0)
 3.4.5 (identical to 3.4.0)
 3.4.6 (identical to 3.4.0)
+
+# 3.5
+3.5.0