Change build to autoname latest.json as YYYY-MM-DD.json

Closes GH-5.

Reviewed-by: Titus Wormer <tituswormer@gmail.com>

readme.md

@@ -71,7 +71,6 @@ You need a `NPM_TOKEN` environment variable with a token to crawl npm.
 
 [`script/crawl.js`][crawl] analyzes the `package.json` files of `latest`
 releases of [high-impact][] npm packages.
-After running it, please rename `data/latest.json` to the current date.
 This script finishes in about 5 minutes.
 You should likely first contribute to `npm-high-impact`, which can take like
 24 hours to complete.

script/crawl.js

@@ -26,7 +26,13 @@ if (!token) {
 
 let slice = 0
 const size = 20
-const destination = new URL('../data/latest.json', import.meta.url)
+const now = new Date()
+const destination = new URL(
+  `../data/${now.getUTCFullYear()}-${
+    now.getUTCMonth() + 1
+  }-${now.getUTCDate()}.json`,
+  import.meta.url
+)
 
 /** @type {Record<string, Style>} */
 const allResults = {}