docs,workflows: remove or update references to packages/core(-api)

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

docs/auth/oauth.md

@@ -14,7 +14,7 @@ to various third party APIs.
 There are occasions when the user wants to perform actions towards third party
 services that require authorization via OAuth. Backstage provides standardized
 [Utility APIs](../api/utility-apis.md) such as the
-[GoogleAuthApi](https://github.com/backstage/backstage/blob/master/packages/core-api/src/apis/definitions/auth.ts)
+[GoogleAuthApi](https://github.com/backstage/backstage/blob/master/packages/core-plugin-api/src/apis/definitions/auth.ts)
 for that use-case. Backstage also includes a set of implementations of these
 APIs that integrate with the
 [auth-backend](https://github.com/backstage/backstage/tree/master/plugins/auth-backend)
@@ -59,7 +59,7 @@ easier to make authenticated requests inside a plugin.
 The following describes the OAuth flow implemented by the
 [auth-backend](https://github.com/backstage/backstage/tree/master/plugins/auth-backend)
 and
-[DefaultAuthConnector](https://github.com/backstage/backstage/blob/master/packages/core-api/src/lib/AuthConnector/DefaultAuthConnector.ts)
+[DefaultAuthConnector](https://github.com/backstage/backstage/blob/master/packages/core-app-api/src/lib/AuthConnector/DefaultAuthConnector.ts)
 in `@backstage/core-api`.
 
 Component and APIs can request Access or ID Tokens from any available Auth