Recognize composer-plugin-api as a platform package, fixes #7951

src/Composer/Repository/PlatformRepository.php

@@ -27,7 +27,7 @@ use Symfony\Component\Process\ExecutableFinder;
  */
 class PlatformRepository extends ArrayRepository
 {
-    const PLATFORM_PACKAGE_REGEX = '{^(?:php(?:-64bit|-ipv6|-zts|-debug)?|hhvm|(?:ext|lib)-[a-z0-9](?:[_.-]?[a-z0-9]+)*)$}iD';
+    const PLATFORM_PACKAGE_REGEX = '{^(?:php(?:-64bit|-ipv6|-zts|-debug)?|hhvm|(?:ext|lib)-[a-z0-9](?:[_.-]?[a-z0-9]+)*|composer-plugin-api)$}iD';
 
     private $versionParser;