Update .dockerignore

Author: raidensakura

.dockerignore

@@ -130,26 +130,27 @@ dmypy.json
 package-lock.json
 node_modules/
 
-# Modmail
+# Unused Modmail files
 config.json
 plugins/
 !plugins/registry.json
 !plugins/@local/
 temp/
 test.py
 
-# Other stuff
-requirements.txt
+# Unused repository files
 .env.example
 .gitignore
 .dockerignore
 .github/
+.pre-commit-config.yaml
 app.json
 Procfile
 *.md
 .*.json
 Dockerfile
 docker-compose.yml
+requirements.txt
 LICENSE
 PRIVACY.md