Remove OAuth2ErrorCodes2

Closes gh-368

oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/core/OAuth2ErrorCodes2.java

@@ -1,30 +0,0 @@
-/*
- * Copyright 2020 the original author or authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      https://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.springframework.security.oauth2.core;
-
-/**
- * TODO
- * This class is temporary and will be removed after upgrading to Spring Security 5.5.0 GA.
- *
- * @author Joe Grandja
- * @since 0.0.3
- * @see <a target="_blank" href="https://github.com/spring-projects/spring-security/issues/9184">Issue gh-9184</a>
- */
-public interface OAuth2ErrorCodes2 extends OAuth2ErrorCodes {
-
-	String UNSUPPORTED_TOKEN_TYPE = "unsupported_token_type";
-
-}