feat: fix .nvmrc template to 18.18.0

Author: JoshuaKGoldberg

src/steps/writing/creation/rootFiles.ts

@@ -46,7 +46,7 @@ export async function createRootFiles(options: Options) {
 				},
 			}),
 		}),
-		".nvmrc": `18.17.1\n`,
+		".nvmrc": `18.18.0\n`,
 		".prettierignore": formatIgnoreFile([
 			...(options.excludeContributors ? [] : [".all-contributorsrc"]),
 			...(options.excludeTests ? [] : ["coverage/"]),