typing: Add py.typed file

No one should be using this as a library, but if for some crazy reason
they are, they'll now have hints they can use.

We also add the 'Typing:: Typed' classifier as well as a missing Python
3.14 classifier (it's tested).

Change-Id: Ia49bc6140cdf3783741c62c0fa98a407838fca7f
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

Author: stephenfin

openstackclient/py.typed

@@ -24,6 +24,8 @@ classifiers = [
   "Programming Language :: Python :: 3.11",
   "Programming Language :: Python :: 3.12",
   "Programming Language :: Python :: 3.13",
+  "Programming Language :: Python :: 3.14",
+  "Typing :: Typed",
 ]
 
 [project.urls]