Update dependency ajv to v8

Author: renovate[bot]

packages/admin-api-schema/package.json

@@ -26,7 +26,7 @@
   },
   "dependencies": {
     "@tryghost/errors": "^1.2.26",
-    "ajv": "^6.12.6",
+    "ajv": "^8.0.0",
     "lodash": "^4.17.11"
   }
 }

yarn.lock

@@ -3026,7 +3026,7 @@ aggregate-error@^3.0.0:
     clean-stack "^2.0.0"
     indent-string "^4.0.0"
 
-ajv@^6.10.0, ajv@^6.12.4, ajv@^6.12.6:
+ajv@^6.10.0, ajv@^6.12.4:
   version "6.12.6"
   resolved "https://registry.yarnpkg.com/ajv/-/ajv-6.12.6.tgz#baf5a62e802b07d977034586f8c3baf5adf26df4"
   integrity sha512-j3fVLgvTo527anyYyJOGTYJbG+vnnQYvE0m5mmkc1TK+nxAppkCLMIL0aZ4dblVCNoGShhm+kzE4ZUykBoMg4g==
@@ -3036,7 +3036,7 @@ ajv@^6.10.0, ajv@^6.12.4, ajv@^6.12.6:
     json-schema-traverse "^0.4.1"
     uri-js "^4.2.2"
 
-ajv@^8.0.1:
+ajv@^8.0.0, ajv@^8.0.1:
   version "8.12.0"
   resolved "https://registry.yarnpkg.com/ajv/-/ajv-8.12.0.tgz#d1a0527323e22f53562c567c00991577dfbe19d1"
   integrity sha512-sRu1kpcO9yLtYxBKvqfTeh9KzZEwO3STyX1HT+4CaDzC6HpTGYhIhPIzj9XuKU7KYDwnaeh5hcOwjy1QuJzBPA==