Added a README for vectors, for the benefit of twine check (#11589)

noxfile.py

@@ -161,6 +161,14 @@ def docs(session: nox.Session) -> None:
     session.run(
         "python3", "-m", "readme_renderer", "README.rst", "-o", "/dev/null"
     )
+    session.run(
+        "python3",
+        "-m",
+        "readme_renderer",
+        "vectors/README.rst",
+        "-o",
+        "/dev/null",
+    )
 
 
 @nox.session(name="docs-linkcheck")

vectors/README.rst

@@ -0,0 +1,5 @@
+pyca/cryptography vectors
+=========================
+
+This package contains test vectors which are used in ``pyca/cryptography``'s
+tests.

vectors/pyproject.toml

@@ -9,6 +9,7 @@ authors = [
     {name = "The Python Cryptographic Authority and individual contributors", email = "cryptography-dev@python.org"}
 ]
 description = "Test vectors for the cryptography package."
+readme = "README.rst"
 license = {text = "Apache-2.0 OR BSD-3-Clause"}
 
 [project.urls]