Fix the migration-helper package.

package.json

@@ -15,10 +15,10 @@
     "test": "xo && stylelint 'source/**/*.scss' && tsc"
   },
   "dependencies": {
+    "@holllo/migration-helper": "^0.1.2",
     "caret-pos": "^2.0.0",
     "debounce": "^1.2.1",
     "htm": "^3.1.0",
-    "migration-helper": "^0.1.2",
     "modern-normalize": "^1.1.0",
     "platform": "^1.3.6",
     "preact": "^10.6.6",

source/migrations.ts

@@ -1,4 +1,4 @@
-import {Migration} from 'migration-helper';
+import {Migration} from '@holllo/migration-helper';
 
 export const migrations: Array<Migration<string>> = [
   {