Link provided to swagger blog is for OpenApi 2.0 not 3.0

[ipichris]

The link in the README.md is for version 2.0 of the spec
https://github.com/openapi-tools/swagger-maven-plugin#properties-of-swagger-model
https://swagger.io/blog/api-development/customizing-your-auto-generated-swagger-definition/

specifically the properties basePath, schemes, host were replaced by "servers" config as described here: https://swagger.io/docs/specification/api-host-and-base-path/

Did cost me some time to realize this which cost me way too long.

It would be nice to document all implemented config as not everything is implemented yet. In #58 there was an TODO added which states some of the missing properties: https://github.com/openapi-tools/swagger-maven-plugin/pull/58/files#diff-ad93ce60fb68b7e1422be9ba9083ec58