fix rendering of stars in README (#17477)

Author: individual-it

README.md

@@ -25,7 +25,7 @@
 
 <div align="center">
 
-:star::star::star: If you would like to contribute, please refer to [guidelines](CONTRIBUTING.md) and a list of [open tasks](https://github.com/openapitools/openapi-generator/issues?q=is%3Aopen+is%3Aissue+label%3A%22help+wanted%22).:star::star::star:
+:star::star::star: If you would like to contribute, please refer to [guidelines](CONTRIBUTING.md) and a list of [open tasks](https://github.com/openapitools/openapi-generator/issues?q=is%3Aopen+is%3Aissue+label%3A%22help+wanted%22). :star::star::star:
 
 :bangbang: To migrate from Swagger Codegen to OpenAPI Generator, please refer to the [migration guide](docs/migration-from-swagger-codegen.md) :bangbang: