Fixes typo in package name (#1759)

Author: mvhirsch

docs/guide/migrating-to-v5.md

@@ -7,7 +7,7 @@ v5 is mostly a cleanup release with updated dependencies. The main changes are:
 * Minimum required PHP version is now 7.4
 * The legacy `TokenAnalyser` and the `--legacy` CLI option have been removed
 * Defaults now prefer attributes over annotations
-* PHP parsing now uses `nicic/php-parser`
+* PHP parsing now uses `nikic/php-parser`
 * Removal of deprecated features
   * empty/unused `ProcessorInterface`
   * `Context::clone()` and `Context::detect()`