Merge pull request #10039 from josh31416/fix_issue9475

[docs] Maven repo missing 3.x.x versions

Author: frantuma

README.md

@@ -179,8 +179,12 @@ Swagger Codegen Version    | Release Date | OpenAPI Spec compatibility | Notes
 If you're looking for the latest stable version, you can grab it directly from Maven.org (Java 8 runtime at a minimum):
 
 ```sh
+# Download current stable 2.x.x branch (Swagger and OpenAPI version 2)
 wget https://repo1.maven.org/maven2/io/swagger/swagger-codegen-cli/2.4.12/swagger-codegen-cli-2.4.12.jar -O swagger-codegen-cli.jar
 
+# Download current stable 3.x.x branch (OpenAPI version 3)
+wget https://repo1.maven.org/maven2/io/swagger/codegen/v3/swagger-codegen-cli/3.0.16/swagger-codegen-cli-3.0.16.jar -O swagger-codegen-cli.jar
+
 java -jar swagger-codegen-cli.jar help
 ```