Fixes #3460 -- deprecate OpenSSL 1.0.1 (#4427)

* Fixes #3460 -- deprecate OpenSSL 1.0.1

* We need to import warnings

* flake8

* words are hard

* rephrase
diff --git a/docs/installation.rst b/docs/installation.rst
index d665dbc..2d9db66 100644
--- a/docs/installation.rst
+++ b/docs/installation.rst
@@ -30,6 +30,10 @@
 * ``OpenSSL 1.1.0-latest``
 * ``OpenSSL 1.1.1-latest``
 
+.. warning::
+    Cryptography 2.4 has deprecated support for OpenSSL 1.0.1.
+
+
 Building cryptography on Windows
 --------------------------------