Attempt to fix Yarn issue with @babel/preset-env

Locally I get the following

> warning Pattern ["@babel/preset-env@^7.16.8"] is trying to unpack in
> the same destination
> "/Users/jakob/Library/Caches/Yarn/v6/npm-@babel-preset-env-7.16.8-e682fa0bcd1cf49621d64a8956318ddfb9a05af9-integrity/node_modules/@babel/preset-env"
> as pattern ["@babel/preset-env@^7.15.6"]. This could result in
> non-deterministic behavior, skipping.

According to yarnpkg/yarn#4812 this might be
caused by Yarn failing to correct a merge conflict in yarn.lock, and we
have seen some of those.

package.json

@@ -7,7 +7,7 @@
     "@babel/plugin-syntax-dynamic-import": "^7.0.0",
     "@babel/plugin-transform-runtime": "^7.14.5",
     "@babel/polyfill": "^7.0.0",
-    "@babel/preset-env": "^7.10.3",
+    "@babel/preset-env": "^7.16.8",
     "@rails/ujs": "^6.1.4",
     "@rails/webpacker": "^6.0.0-rc.6",
     "autoprefixer": "^10.3.3",