Change to require Node.js 16

Author: wooorm

readme.md

@@ -159,7 +159,7 @@ versions of Node.js.
 When we cut a new major release, we drop support for unmaintained versions of
 Node.
 This means we try to keep the current release line,
-`hast-util-shift-heading@^3`, compatible with Node.js 12.
+`hast-util-shift-heading@^4`, compatible with Node.js 16.
 
 ## Security
 

tsconfig.json

@@ -5,10 +5,10 @@
     "declaration": true,
     "emitDeclarationOnly": true,
     "exactOptionalPropertyTypes": true,
-    "lib": ["es2020"],
+    "lib": ["es2022"],
     "module": "node16",
     "strict": true,
-    "target": "es2020"
+    "target": "es2022"
   },
   "exclude": ["coverage/", "node_modules/"],
   "include": ["**/*.js"]