Added support for Node 20

ref https://linear.app/tryghost/issue/ENG-765/add-support-for-node-20

- this adds support for Node 20 to Ghost and CI, as Node 20 is an LTS
  version

.github/workflows/ci.yml

@@ -417,7 +417,7 @@ jobs:
     if: needs.job_get_metadata.outputs.changed_any_code == 'true'
     strategy:
       matrix:
-        node: [ '18.12.1' ]
+        node: [ '18.12.1', '20.11.1' ]
     name: Unit tests (Node ${{ matrix.node }})
     steps:
       - uses: actions/checkout@v4
@@ -455,7 +455,7 @@ jobs:
     if: needs.job_get_metadata.outputs.changed_core == 'true'
     strategy:
       matrix:
-        node: [ '18.12.1' ]
+        node: [ '18.12.1', '20.11.1' ]
         env:
           - DB: mysql8
             NODE_ENV: testing-mysql

ghost/admin/package.json

@@ -26,7 +26,7 @@
     "lint": "yarn lint:js && yarn lint:hbs"
   },
   "engines": {
-    "node": "^18.12.1"
+    "node": "^18.12.1 || ^20.11.1"
   },
   "devDependencies": {
     "@babel/eslint-parser": "7.23.3",
@@ -201,4 +201,4 @@
       }
     }
   }
-}
+}

ghost/core/package.json

@@ -53,7 +53,7 @@
     "prepack": "node monobundle.js"
   },
   "engines": {
-    "node": "^18.12.1",
+    "node": "^18.12.1 || ^20.11.1",
     "cli": "^1.25.0"
   },
   "dependencies": {