ci: skip builds when only docs change

Author: zfarrell

.github/workflows/ci.yml

@@ -3,8 +3,16 @@ name: CI
 on:
   push:
     branches: [ main ]
+    paths-ignore:
+      - '**.md'
+      - 'LICENSE'
+      - '.gitignore'
   pull_request:
     branches: [ main ]
+    paths-ignore:
+      - '**.md'
+      - 'LICENSE'
+      - '.gitignore'
 
 env:
   RUST_BACKTRACE: 1