fix: update read-pkg-up usage to work with version 7

`read-pkg-up` was updated from version `6` to `7` in a89e02e
But the breaking change explained here https://github.com/sindresorhus/read-pkg-up/releases/tag/v7.0.0 wasn't applied so I just applied it

addons/storyshots/storyshots-core/src/frameworks/hasDependency.js

@@ -2,7 +2,7 @@ import fs from 'fs';
 import path from 'path';
 import readPkgUp from 'read-pkg-up';
 
-const { package: { dependencies, devDependencies } = {} } = readPkgUp.sync() || {};
+const { packageJson: { dependencies, devDependencies } = {} } = readPkgUp.sync() || {};
 
 export default function hasDependency(name) {
   return (