chore(deps-dev): bump esbuild from 0.20.2 to 0.21.0

Bumps [esbuild](https://github.com/evanw/esbuild) from 0.20.2 to 0.21.0.
- [Release notes](https://github.com/evanw/esbuild/releases)
- [Changelog](https://github.com/evanw/esbuild/blob/main/CHANGELOG.md)
- [Commits](evanw/esbuild@v0.20.2...v0.21.0)

---
updated-dependencies:
- dependency-name: esbuild
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -21,7 +21,7 @@
     "gh-release": "^7.0.0",
     "npm-run-all2": "^6.0.0",
     "standard": "^17.0.0",
-    "esbuild": "^0.20.0"
+    "esbuild": "^0.21.0"
   },
   "homepage": "https://github.com/bcomnes/deploy-to-neocities#readme",
   "keywords": [],