Prepare release

Author: sebastianbergmann

ChangeLog-13.1.md

@@ -2,7 +2,7 @@
 
 All notable changes of the PHPUnit 13.1 release series are documented in this file using the [Keep a CHANGELOG](https://keepachangelog.com/) principles.
 
-## [13.1.8] - 2026-MM-DD
+## [13.1.8] - 2026-05-01
 
 ### Fixed
 
@@ -107,7 +107,7 @@ 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
 
-[13.1.8]: https://github.com/sebastianbergmann/phpunit/compare/13.1.7...13.1
+[13.1.8]: https://github.com/sebastianbergmann/phpunit/compare/13.1.7...13.1.8
 [13.1.7]: https://github.com/sebastianbergmann/phpunit/compare/13.1.6...13.1.7
 [13.1.6]: https://github.com/sebastianbergmann/phpunit/compare/13.1.5...13.1.6
 [13.1.5]: https://github.com/sebastianbergmann/phpunit/compare/13.1.4...13.1.5

src/Runner/Version.php

@@ -35,7 +35,7 @@ public static function id(): string
         }
 
         if (self::$version === '') {
-            self::$version = new VersionId('13.1.7', dirname(__DIR__, 2))->asString();
+            self::$version = new VersionId('13.1.8', dirname(__DIR__, 2))->asString();
         }
 
         return self::$version;