Update dependency mkdirp to v3

Author: renovate[bot]

package.json

@@ -17,7 +17,7 @@
     "bunyan": "1.8.15",
     "eslint": "7.21.0",
     "eslint-plugin-ghost": "2.0.0",
-    "mkdirp": "1.0.4",
+    "mkdirp": "3.0.0",
     "mocha": "8.3.0",
     "should": "13.2.3",
     "sinon": "9.2.4"

yarn.lock

@@ -1027,10 +1027,10 @@ minimist@^1.2.5:
   resolved "https://registry.yarnpkg.com/minimist/-/minimist-1.2.5.tgz#67d66014b66a6a8aaa0c083c5fd58df4e4e97602"
   integrity sha512-FM9nNUYrRBAELZQT3xeZQ7fmMOBg6nWNmJKTcgsJeaLstP/UODVpGsr5OhXhhXg6f+qtJ8uiZ+PUxkDWcgIXLw==
 
-mkdirp@1.0.4:
-  version "1.0.4"
-  resolved "https://registry.yarnpkg.com/mkdirp/-/mkdirp-1.0.4.tgz#3eb5ed62622756d79a5f0e2a221dfebad75c2f7e"
-  integrity sha512-vVqVZQyf3WLx2Shd0qJ9xuvqgAyKPLAiqITEtqW0oIUjzo3PePDd6fW9iFz30ef7Ysp/oiWqbhszeGWW2T6Gzw==
+mkdirp@3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/mkdirp/-/mkdirp-3.0.0.tgz#758101231418bda24435c0888a91d9bd91f1372d"
+  integrity sha512-7+JDnNsyCvZXoUJdkMR0oUE2AmAdsNXGTmRbiOjYIwQ6q+bL6NwrozGQdPcmYaNcrhH37F50HHBUzoaBV6FITQ==
 
 mkdirp@^0.5.1, mkdirp@~0.5.1:
   version "0.5.5"