Prepare 2.13.1.0 release. (#188)

* Prepare 2.13.1.0 release.
* Update Win32.cabal

Author: Mistuke

Win32.cabal

@@ -1,5 +1,5 @@
 name:           Win32
-version:        2.13.0.0
+version:        2.13.1.0
 license:        BSD3
 license-file:   LICENSE
 author:         Alastair Reid, shelarcy, Tamar Christina

changelog.md

@@ -1,9 +1,10 @@
 # Changelog for [`Win32` package](http://hackage.haskell.org/package/Win32)
 
-## next
+## 2.13.1.0 November 2021
 
 * Fix a bug in which `System.Win32.MinTTY.isMinTTY` would incorrectly return
-  `False` on recent versions of MinTTY.
+  `False` on recent versions of MinTTY. (See #187)
+* Add all flags for CreateToolhelp32Snapshot.  (See #185)
 
 ## 2.13.0.0 August 2021