rename npm namespace from @spotify-backstage to @backstage

docs/getting-started/Plugin development.md

@@ -40,7 +40,7 @@ The app will call the `createPlugin` method on each plugin, passing in a `router
 of methods on it.
 
 ```typescript
-import { createPlugin } from '@spotify-backstage/core';
+import { createPlugin } from '@backstage/core';
 import ExampleComponent from './components/ExampleComponent';
 
 export default createPlugin({

docs/getting-started/structure-of-a-plugin.md

@@ -43,7 +43,7 @@ In the root folder you have some configuration for typescript and jest, the test
 In the `src` folder we get to the interesting bits. Check out the `plugin.ts`:
 
 ```jsx
-import { createPlugin } from '@spotify-backstage/core';
+import { createPlugin } from '@backstage/core';
 import ExampleComponent from './components/ExampleComponent';
 
 export default createPlugin({