Remove basePath: "/"

[navinger]

I'm updating all the openapi files in the getting-started sample in all the sample repos to remove basePath: "/"
Here's the reason from simonz130:

From the OpenAPI 2 spec:

• basePath: "If it is not included, the API is served directly under the host. The value MUST start with a leading slash (/). "
• Paths for methods: "A relative path to an individual endpoint. The field name MUST begin with a slash. The path is appended to the basePath in order to construct the full URL."

This OpenAPI getting-started sample have basePath: "/", which (per strict spec interpretation) means all the paths start with double-slashes. (e.g "//v1/shelves" rather than "/v1/shelves"). Removing basepath="/" fixes that.

[lesv]

- testing endpoints/getting-started
------------------------------------------------------------
[ERROR] src/main/java/com/example/endpoints/AuthInfoServlet.java:[1] (header) RegexpHeader: Line does not match expected header line of '^\W+\*?\W*Copyright 20\d\d Google Inc.$'.
[ERROR] src/main/java/com/example/endpoints/EchoServlet.java:[1] (header) RegexpHeader: Line does not match expected header line of '^\W+\*?\W*Copyright 20\d\d Google Inc.$'.
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-checkstyle-plugin:2.17:check (default) on project endpoints: You have 2 Checkstyle violations. -> [Help 1]

[lesv]

@dzlier-gcp Could you fix this for Nancy and the other one?
@kurtisvg I looked at the header and don't see what's wrong.

[kurtisvg]

I'm going to merge this into #1077.