feat: Implement update credentials endpoint

packages/backend/src/graphql/root-mutation.ts

@@ -1,12 +1,14 @@
 import { GraphQLObjectType } from 'graphql';
 import createCredential from './mutations/create-credential';
 import createAuthLink from './mutations/create-auth-link';
+import updateCredential from './mutations/update-credential';
 
 const rootMutation = new GraphQLObjectType({
   name: 'Mutation',
   fields: {
     createCredential: createCredential,
-    createAuthLink: createAuthLink
+    createAuthLink: createAuthLink,
+    updateCredential: updateCredential
   }
 });