Omit readme from the output.

cotes2020 · cotes2020 · commit e6de482e5a3c · 2020-04-09T03:08:56.000+08:00
diff --git a/_config.yml b/_config.yml
@@ -186,6 +186,7 @@ exclude:
   - Gemfile
   - tools
   - docs
+  - README.md
 
 sitemap_exclude:  # Sitemap will exclude the following items.
   fuzzy:
