Ingore node_modules when building the site

PeterJCLaw · PeterJCLaw · commit 3bc46c9328cf · 2022-10-02T14:56:37.000+01:00
This won't be present when GitHub Pages builds the site, so having
it present is merely likely to create confusion (as well as slow
down the build locally/in CI).
diff --git a/_config.yml b/_config.yml
@@ -57,6 +57,7 @@ exclude:
   - gems/
   - Dockerfile
   - docker-compose.yml
+  - node_modules/
   - _env/
   - _docs/
   - vendor/
