fix link to openapi-generator in README

Author: pavog

README.md

@@ -232,7 +232,7 @@ $project = $version->getProject();
 ```
 
 ## Updating the generated code
-Update the generated code by installing the (openapi generator)[https://openapi-generator.tech/docs/installation] and running:
+Update the generated code by installing the [openapi generator](https://openapi-generator.tech/docs/installation) and running:
 ```bash
 openapi-generator-cli generate -c config.yaml
 ```
@@ -252,4 +252,4 @@ Integration tests perform real requests against the live SpigotMC API.
 Run only integration tests:
 ```bash
 vendor/bin/phpunit --testsuite=integration --testdox
-```
+```