Pin govuk-frontend to v4.0.1

package.json

@@ -20,7 +20,7 @@
     "css-loader": "^6.7.1",
     "custom-event-polyfill": "^1.0.7",
     "file-loader": "^6.2.0",
-    "govuk-frontend": "^4.0.1",
+    "govuk-frontend": "4.0.1",
     "govuk-prototype-components": "^0.1.5",
     "html5shiv": "^3.7.3",
     "intersection-observer": "^0.12.0",

yarn.lock

@@ -2402,6 +2402,11 @@ globjoin@^0.1.4:
   resolved "https://registry.yarnpkg.com/globjoin/-/globjoin-0.1.4.tgz#2f4494ac8919e3767c5cbb691e9f463324285d43"
   integrity sha512-xYfnw62CKG8nLkZBfWbhWwDw02CHty86jfPcc2cr3ZfeuK9ysoVPPEUxf21bAD/rWAgk52SuBrLJlefNy8mvFg==
 
+govuk-frontend@4.0.1:
+  version "4.0.1"
+  resolved "https://registry.yarnpkg.com/govuk-frontend/-/govuk-frontend-4.0.1.tgz#bceff58ecb399272cba32bd2b357fe16198e3249"
+  integrity sha512-X+B88mqYHoxAz0ID87Uxo3oHqdKBRnNHd3Cz8+u8nvQUAsrEzROFLK+t7sAu7e+fKqCCrJyIgx6Cmr6dIGnohQ==
+
 govuk-frontend@^4.0.1:
   version "4.0.1"
   resolved "https://registry.yarnpkg.com/govuk-frontend/-/govuk-frontend-4.0.1.tgz#bceff58ecb399272cba32bd2b357fe16198e3249"