Export Token types from core.d.ts (#4292)

Fixes #4291

.changes/next-release/bugfix-Token-ee8a4626.json

@@ -0,0 +1,5 @@
+{
+  "type": "bugfix",
+  "category": "Token",
+  "description": "Export Token types from core.d.ts"
+}

lib/core.d.ts

@@ -16,6 +16,10 @@ export {TemporaryCredentials} from './credentials/temporary_credentials';
 export {ChainableTemporaryCredentials} from './credentials/chainable_temporary_credentials';
 export {WebIdentityCredentials} from './credentials/web_identity_credentials';
 export {TokenFileWebIdentityCredentials} from './credentials/token_file_web_identity_credentials';
+export {Token} from './token';
+export {StaticTokenProvider} from './token/static_token_provider';
+export {SSOTokenProvider} from './token/sso_token_provider';
+export {TokenProviderChain} from './token/token_provider_chain';
 export {Endpoint} from './endpoint';
 export {EventListeners} from './event_listeners';
 export {HttpRequest} from './http_request';