Update version numbers etc for v1.13.1 release

Author: wilfwilson

.VERSION

@@ -1 +1 @@
-1.13.0
+1.13.1

CHANGELOG.md

@@ -4,6 +4,16 @@ Wilf A. Wilson, Michael Young et al.
 
 Licensing information can be found in the `LICENSE` file.
 
+## Version 1.13.1 (released 27/09/2025)
+
+This is a minor release of the Digraphs package, containing one bugfix.
+
+## What's Changed
+* In [PR #852](https://github.com/digraphs/Digraphs/pull/852), [@wilfwilson](https://github.com/wilfwilson) fixed a bug that could result in an incorrect result being given for the `AutomorphismGroup` for a digraph that was created by the `CompleteBipartiteDigraph` operation.
+    * This bug was reported by [@bojankuzma000](https://github.com/bojankuzma000) in [Issue #850](https://github.com/digraphs/Digraphs/issues/850).
+
+**Full Changelog**: <https://github.com/digraphs/Digraphs/compare/v1.13.0...v1.13.1>
+
 ## Version 1.13.0 (released 26/09/2025)
 
 ## What's Changed

PackageInfo.g

@@ -38,8 +38,8 @@ fi;
 SetPackageInfo(rec(
 PackageName := "Digraphs",
 Subtitle := "Graphs, digraphs, and multidigraphs in GAP",
-Version := "1.13.0",
-Date := "26/09/2025",  # dd/mm/yyyy format
+Version := "1.13.1",
+Date := "27/09/2025",  # dd/mm/yyyy format
 License := "GPL-3.0-or-later",
 ArchiveFormats := ".tar.gz",
 

VERSIONS

@@ -8,6 +8,7 @@
 #############################################################################
 ##
 
+release 1.13.1 - 27/09/2025
 release 1.13.0 - 26/09/2025
 release 1.12.2 - 20/09/2025
 release 1.12.1 - 10/09/2025