Use go.mod ignore directive instead of postinstall

Herebyfile.mjs

@@ -477,16 +477,6 @@ export const checkFormat = task({
     },
 });
 
-export const postinstall = task({
-    name: "postinstall",
-    hiddenFromTaskList: true,
-    run: () => {
-        // Ensure the go command doesn't waste time looking into node_modules.
-        // Remove once https://github.com/golang/go/issues/42965 is fixed.
-        fs.writeFileSync(path.join(__dirname, "node_modules", "go.mod"), `module example.org/ignoreme\n`);
-    },
-});
-
 /**
  * @param {string} localBaseline Path to the local copy of the baselines
  * @param {string} refBaseline Path to the reference copy of the baselines

go.mod

@@ -28,3 +28,12 @@ tool (
 	golang.org/x/tools/cmd/stringer
 	mvdan.cc/gofumpt
 )
+
+ignore (
+	./_extension
+	./_packages
+	./_submodules
+	./built
+	./coverage
+	node_modules
+)

package.json

@@ -19,7 +19,6 @@
         "which": "^5.0.0"
     },
     "scripts": {
-        "postinstall": "hereby postinstall",
         "build": "hereby build",
         "build:watch": "hereby build:watch",
         "build:watch:debug": "hereby build:watch --debug",