rename npm namespace from @spotify-backstage to @backstage

plugins/welcome/src/components/Timer/Timer.tsx

@@ -15,7 +15,7 @@
  */
 
 import React, { FC } from 'react';
-import { HeaderLabel } from '@spotify-backstage/core';
+import { HeaderLabel } from '@backstage/core';
 
 const timeFormat = { hour: '2-digit', minute: '2-digit' };
 const utcOptions = { timeZone: 'UTC', ...timeFormat };

plugins/welcome/src/components/WelcomePage/ErrorButton.test.tsx

@@ -17,7 +17,7 @@
 import React from 'react';
 import { render, fireEvent } from '@testing-library/react';
 import ErrorButton from './ErrorButton';
-import { ApiRegistry, errorApiRef, ApiProvider } from '@spotify-backstage/core';
+import { ApiRegistry, errorApiRef, ApiProvider } from '@backstage/core';
 
 describe('ErrorButton', () => {
   it('should trigger an error', () => {

plugins/welcome/src/components/WelcomePage/ErrorButton.tsx

@@ -16,7 +16,7 @@
 
 import React, { FC } from 'react';
 import { Button } from '@material-ui/core';
-import { errorApiRef, useApi } from '@spotify-backstage/core';
+import { errorApiRef, useApi } from '@backstage/core';
 
 const ErrorButton: FC<{}> = () => {
   const errorApi = useApi(errorApiRef);

plugins/welcome/src/components/WelcomePage/WelcomePage.test.tsx

@@ -23,7 +23,7 @@ import {
   ApiProvider,
   ApiRegistry,
   errorApiRef,
-} from '@spotify-backstage/core';
+} from '@backstage/core';
 
 describe('WelcomePage', () => {
   it('should render', () => {

plugins/welcome/src/components/WelcomePage/WelcomePage.tsx

@@ -33,7 +33,7 @@ import {
   pageTheme,
   ContentHeader,
   SupportButton,
-} from '@spotify-backstage/core';
+} from '@backstage/core';
 import ErrorButton from './ErrorButton';
 
 const WelcomePage: FC<{}> = () => {

plugins/welcome/src/plugin.ts

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { createPlugin } from '@spotify-backstage/core';
+import { createPlugin } from '@backstage/core';
 import WelcomePage from './components/WelcomePage';
 
 export default createPlugin({