build: ignore running ci when changing only markdown files. (#119)

Author: mpaulucci

.github/workflows/ci.yml

@@ -5,6 +5,8 @@ on:
     branches: [ main ]
   pull_request:
     branches: [ '*' ]
+    paths-ignore:
+      - '**/*.md'
 
 env:
   MIX_ENV: test