[meta] use npmignore to autogenerate an npmignore file

.gitignore

@@ -6,3 +6,5 @@ node_modules/
 npm-shrinkwrap.json
 package-lock.json
 yarn.lock
+
+.npmignore

package.json

@@ -12,10 +12,12 @@
 		"aud": "^2.0.1",
 		"eslint": "=8.8.0",
 		"in-publish": "^2.0.1",
+		"npmignore": "^0.3.0",
 		"safe-publish-latest": "^2.0.0",
 		"tape": "^5.6.1"
 	},
 	"scripts": {
+		"prepack": "npmignore --auto --commentLines=autogenerated",
 		"prepublish": "not-in-publish || npm run prepublishOnly",
 		"prepublishOnly": "safe-publish-latest",
 		"lint": "eslint --ext=js,mjs .",
@@ -68,5 +70,10 @@
 		"email": "mail@substack.net",
 		"url": "http://substack.net"
 	},
-	"license": "MIT"
+	"license": "MIT",
+	"publishConfig": {
+		"ignore": [
+			".github/workflows"
+		]
+	}
 }