dots lost when dereferencing files with dots

[simonhege]

Hello

Following fix for https://github.com/swagger-api/swagger-parser/issues/1865 the name of the schema lost the dots

The name of the schema being of importance in the code generation, I think the swagger-parser should keep the dots as per the referenced file name

This mean that at https://github.com/swagger-api/swagger-parser/blob/master/modules/swagger-parser-v3/src/test/java/io/swagger/v3/parser/test/OpenAPIV3ParserTest.java#L115 I expect to see #/components/schemas/foo.model instead of #/components/schemas/foomodel

[simonhege]

If you agree with this, I'll submit a pull-request for the change.

[simonhege]

Ping @gracekarina as you did the original fix on https://github.com/swagger-api/swagger-parser/issues/1865