[meta] use npmignore to autogenerate an npmignore file

.gitignore

@@ -37,3 +37,5 @@ node_modules
 npm-shrinkwrap.json
 package-lock.json
 yarn.lock
+
+.npmignore

package.json

@@ -19,6 +19,7 @@
 		"./package.json": "./package.json"
 	},
 	"scripts": {
+		"prepack": "npmignore --auto --commentLines=autogenerated",
 		"prepublish": "not-in-publish || npm run prepublishOnly",
 		"prepublishOnly": "safe-publish-latest",
 		"lint": "eslint --ext=js,mjs .",
@@ -51,6 +52,10 @@
 		"url": "https://github.com/es-shims/Object.hasOwn/issues"
 	},
 	"homepage": "https://github.com/es-shims/Object.hasOwn",
+	"dependencies": {
+		"define-properties": "^1.1.4",
+		"es-abstract": "^1.19.5"
+	},
 	"devDependencies": {
 		"@es-shims/api": "^2.2.3",
 		"@ljharb/eslint-config": "^20.2.3",
@@ -61,6 +66,7 @@
 		"functions-have-names": "^1.2.3",
 		"has-strict-mode": "^1.0.1",
 		"has-symbols": "^1.0.3",
+		"npmignore": "^0.3.0",
 		"nyc": "^10.3.2",
 		"safe-publish-latest": "^2.0.0",
 		"tape": "^5.5.3"
@@ -73,8 +79,9 @@
 		"backfillLimit": false,
 		"hideCredit": true
 	},
-	"dependencies": {
-		"define-properties": "^1.1.4",
-		"es-abstract": "^1.19.5"
+	"publishConfig": {
+		"ignore": [
+			".github/workflows"
+		]
 	}
 }