Update dependency grunt to v1.5.2 (#2331)

Co-authored-by: Renovate Bot <bot@renovateapp.com>

ghost/admin/package.json

@@ -124,7 +124,7 @@
     "fs-extra": "10.0.1",
     "glob": "7.2.0",
     "google-caja-bower": "https://github.com/acburdine/google-caja-bower#ghost",
-    "grunt": "1.4.1",
+    "grunt": "1.5.2",
     "grunt-shell": "3.0.1",
     "keymaster": "https://github.com/madrobby/keymaster.git",
     "liquid-fire": "0.34.0",

ghost/admin/yarn.lock

@@ -8969,7 +8969,7 @@ growly@^1.3.0:
   resolved "https://registry.yarnpkg.com/growly/-/growly-1.3.0.tgz#f10748cbe76af964b7c96c93c6bcc28af120c081"
   integrity sha1-8QdIy+dq+WS3yWyTxrzCivEgwIE=
 
-grunt-cli@~1.4.2:
+grunt-cli@~1.4.3:
   version "1.4.3"
   resolved "https://registry.yarnpkg.com/grunt-cli/-/grunt-cli-1.4.3.tgz#22c9f1a3d2780bf9b0d206e832e40f8f499175ff"
   integrity sha512-9Dtx/AhVeB4LYzsViCjUQkd0Kw0McN2gYpdmGYKtE2a5Yt7v1Q+HYZVWhqXc/kGnxlMtqKDxSwotiGeFmkrCoQ==
@@ -9025,17 +9025,17 @@ grunt-shell@3.0.1:
     npm-run-path "^2.0.0"
     strip-ansi "^5.0.0"
 
-grunt@1.4.1:
-  version "1.4.1"
-  resolved "https://registry.yarnpkg.com/grunt/-/grunt-1.4.1.tgz#7d1e17db1f9c8108777f7273d6b9359755576f50"
-  integrity sha512-ZXIYXTsAVrA7sM+jZxjQdrBOAg7DyMUplOMhTaspMRExei+fD0BTwdWXnn0W5SXqhb/Q/nlkzXclSi3IH55PIA==
+grunt@1.5.2:
+  version "1.5.2"
+  resolved "https://registry.yarnpkg.com/grunt/-/grunt-1.5.2.tgz#46b014e28d17c85baac19d5e891bb3f04923c098"
+  integrity sha512-XCtfaIu72OyDqK24MjWiGC9SwlkuhkS1mrULr1xzuJ2XqAFhP3ZAchZGHJeSCY6mkaOXU4F7SbmmCF7xIVoC9w==
   dependencies:
     dateformat "~3.0.3"
     eventemitter2 "~0.4.13"
     exit "~0.1.2"
     findup-sync "~0.3.0"
     glob "~7.1.6"
-    grunt-cli "~1.4.2"
+    grunt-cli "~1.4.3"
     grunt-known-options "~2.0.0"
     grunt-legacy-log "~3.0.0"
     grunt-legacy-util "~2.0.1"