add pod-lib-lint command.

Author: sgr-ksmt

Makefile

@@ -10,4 +10,7 @@ pod-install:
 	bundle exec pod install || bundle exec pod install --repo-update
 
 gen-docs:
-	bundle exec jazzy --config .jazzy.yaml
+	bundle exec jazzy --config .jazzy.yaml
+
+pod-lib-lint:
+	bundle exec pod lib lint --allow-warnings