Point deprecation links to specific version of README and make README links to itself relatives

Author: Samanta de Barros

README.md

@@ -445,7 +445,7 @@ export default Base.extend({
 
 __Authorizers use the session data acquired by the authenticator to construct
 authorization data__ that can be injected into outgoing network requests. As
-[Deprecation warning: Authorizers are deprecated](https://github.com/simplabs/ember-simple-auth#deprecation-of-authorizers)
+[Deprecation warning: Authorizers are deprecated](#deprecation-of-authorizers)
 
 the authorizer depends on the data that the authenticator acquires,
 __authorizers and authenticators have to fit together__.

addon/authenticators/oauth2-password-grant.js

@@ -271,7 +271,7 @@ export default BaseAuthenticator.extend({
         {
           id: 'ember-simple-auth.oauth2-password-grant-authenticator.client-id-as-authorization',
           until: '3.0.0',
-          url: 'https://github.com/simplabs/ember-simple-auth#deprecation-of-client-id-as-header',
+          url: 'https://github.com/simplabs/ember-simple-auth/tree/2.0.0#deprecation-of-client-id-as-header',
         }
       );
     }

addon/authorizers/base.js

@@ -30,7 +30,7 @@ export default EmberObject.extend({
       {
         id: 'ember-simple-auth.baseAuthorizer',
         until: '3.0.0',
-        url: 'https://github.com/simplabs/ember-simple-auth#deprecation-of-authorizers',
+        url: 'https://github.com/simplabs/ember-simple-auth/tree/2.0.0#deprecation-of-authorizers',
       }
     );
   },

addon/services/session.js

@@ -238,7 +238,7 @@ export default Service.extend(Evented, {
     deprecate(`Ember Simple Auth: 'authorize' is deprecated.`, false, {
       id: 'ember-simple-auth.session.authorize',
       until: '3.0.0',
-      url: 'https://github.com/simplabs/ember-simple-auth#authorizers'
+      url: 'https://github.com/simplabs/ember-simple-auth/tree/2.0.0#deprecation-of-authorizers'
     });
     if (this.get('isAuthenticated')) {
       const authorizer = getOwner(this).lookup(authorizerFactory);