bpo-29572: Update Windows build to OpenSSL 1.0.2k (GH-444)

diff --git a/PCbuild/python.props b/PCbuild/python.props
index 21ea5fa..486a7c9 100644
--- a/PCbuild/python.props
+++ b/PCbuild/python.props
@@ -35,7 +35,7 @@
     <sqlite3Dir>$(ExternalsDir)sqlite-3.8.11.0\</sqlite3Dir>
     <bz2Dir>$(ExternalsDir)bzip2-1.0.6\</bz2Dir>
     <bsddbDir>$(ExternalsDir)db-4.7.25.0</bsddbDir>
-    <opensslDir>$(ExternalsDir)openssl-1.0.2j\</opensslDir>
+    <opensslDir>$(ExternalsDir)openssl-1.0.2k\</opensslDir>
     <opensslIncludeDir>$(opensslDir)include32</opensslIncludeDir>
     <opensslIncludeDir Condition="'$(ArchName)' == 'amd64'">$(opensslDir)include64</opensslIncludeDir>
     <nasmDir>$(ExternalsDir)\nasm-2.11.06\</nasmDir>