Bump vws-python-mock to 2026.2.22.1

The new release fixes the urljoin bug in MockVWS so it correctly
registers handlers at path-prefixed base URLs. The path-prefix tests
stay as ConnectionError tests: MockVWS listens at the bare URL while
the client uses the prefixed URL, so the prefix being preserved
causes a ConnectionError -- the inverse of the urljoin behaviour where
the prefix would be silently dropped and the mock would respond.

(A fully positive round-trip test is not yet possible because the HMAC
signing also needs to incorporate the base URL path prefix, which is a
separate issue.)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: adamtheturtle

pyproject.toml

@@ -82,7 +82,7 @@ optional-dependencies.dev = [
     "ty==0.0.17",
     "types-requests==2.32.4.20260107",
     "vulture==2.14",
-    "vws-python-mock==2026.2.21",
+    "vws-python-mock==2026.2.22.1",
     "vws-test-fixtures==2023.3.5",
     "yamlfix==1.19.1",
     "zizmor==1.22.0",