Move to @codemirror/buildhelper 1.0.0

Author: marijnh

package.json

@@ -35,7 +35,7 @@
     "@codemirror/view": "^6.0.0"
   },
   "devDependencies": {
-    "@codemirror/buildhelper": "^0.1.5"
+    "@codemirror/buildhelper": "^1.0.0"
   },
   "repository": {
     "type": "git",