bpo-34631: Updated OpenSSL to 1.1.1c in Windows installer (GH-14163)

diff --git a/PCbuild/readme.txt b/PCbuild/readme.txt
index 312fa6a..b32595b 100644
--- a/PCbuild/readme.txt
+++ b/PCbuild/readme.txt
@@ -165,7 +165,7 @@
     Homepage:
         http://tukaani.org/xz/
 _ssl
-    Python wrapper for version 1.1.1b of the OpenSSL secure sockets
+    Python wrapper for version 1.1.1c of the OpenSSL secure sockets
     library, which is downloaded from our binaries repository at
     https://github.com/python/cpython-bin-deps.