Prepare release

Author: sebastianbergmann

ChangeLog-13.1.md

@@ -34,4 +34,4 @@ All notable changes of the PHPUnit 13.1 release series are documented in this fi
 * [#6433](https://github.com/sebastianbergmann/phpunit/issues/6433): Logic in `TestSuiteLoader` is brittle and causes "Class FooTest not found" even for valid tests in valid filenames
 * [#6463](https://github.com/sebastianbergmann/phpunit/issues/6463): Process Isolation fails on non-serializable globals and quietly ignore closures
 
-[13.1.0]: https://github.com/sebastianbergmann/phpunit/compare/13.0...main
+[13.1.0]: https://github.com/sebastianbergmann/phpunit/compare/13.0.6...13.1.0

src/Runner/Version.php

@@ -35,7 +35,7 @@ public static function id(): string
         }
 
         if (self::$version === '') {
-            self::$version = new VersionId('13.1', dirname(__DIR__, 2))->asString();
+            self::$version = new VersionId('13.1.0', dirname(__DIR__, 2))->asString();
         }
 
         return self::$version;