Linkedin: Migrate to versioned APIs

[peternees]

Linkedin changes to versioned api. See: https://learn.microsoft.com/en-us/linkedin/marketing/versioning?trk=eml-mktg-cust-202304-global-api-migrations-june&mcid=7054174543908663296&src=e-eml&view=li-lms-2023-04

This has some impact.

1.Change needed to OAuth20Service

final OAuth20Service service = new ServiceBuilder(clientId)
                .apiSecret(clientSecret)
                .defaultScope(new ScopeBuilder("r_liteprofile", "r_emailaddress"))
                .callback("http://example.com/callback")
                .build(LinkedInApi20.instance());

a. LinkedInApi20 need different endpoints: change v2 to rest

    public String getAccessTokenEndpoint() {
        return "https://www.linkedin.com/oauth/**rest**/accessToken";
    }

    protected String getAuthorizationBaseUrl() {
        return "https://www.linkedin.com/oauth/**rest**/authorization";
    }

This could be solved by using an extention of LinkedInApi20 with the rest endpoint. But it is better that LinkedInApi20 gets updated.

b. the oauth request need to get a version header. I think for this, scribejava lib needs a change

2. Change to Resource api. This is easy and does not require a change of the scribeapi.

In the example https://github.com/scribejava/scribejava/blob/master/scribejava-apis/src/test/java/com/github/scribejava/apis/examples/LinkedIn20Example.java change the resource endpoint:
now:
```
private static final String PROTECTED_RESOURCE_URL = "https://api.linkedin.com/v2/me";
private static final String PROTECTED_EMAIL_RESOURCE_URL
= "https://api.linkedin.com/v2/emailAddress?q=members&projection=(elements*(handle~))";

chage to

private static final String PROTECTED_RESOURCE_URL = "https://api.linkedin.com/**rest**/me";
private static final String PROTECTED_EMAIL_RESOURCE_URL
        = "https://api.linkedin.com/**rest**/emailAddress?q=members&projection=(elements*(handle~))";

..
final OAuthRequest request = new OAuthRequest(Verb.GET, PROTECTED_RESOURCE_URL);
**request.addHeader("LinkedIn-Version", "202304");**

[peternees]

After testing, some additional info (I should have done that before creating the issue):

• https://www.linkedin.com/oauth/rest/authorization does not work. This URL is used with a redirect in the Browser, this is not realy an api request on which you can add headers. I guess/hope this remains v2.
• https://api.linkedin.com/rest/emailAddress?q=members&projection=(elements*(handle~)) does not work. It returns {"status":404,"code":"RESOURCE_NOT_FOUND","message":"No virtual resource found"}. The v2 end point is still valid: https://api.linkedin.com/v2/emailAddress?q=members&projection=(elements*(handle~))"; I don't know if this will change.

So it seems that, for the moment, only the profile api (/me) should change to https://api.linkedin.com/rest/me with version header.

So no need for a change in the lib, but for the linkedin example.