ci: ignore func tests for some target modifications

Author: KazuCocoa

.github/workflows/functional-test.yml

@@ -5,8 +5,16 @@ on:
   workflow_dispatch:
   push:
     branches: [ master ]
+    paths-ignore:
+    - '.github/**'
+    - 'docs/**'
+    - '*.md'
   pull_request:
     branches: [ master ]
+    paths-ignore:
+    - '.github/**'
+    - 'docs/**'
+    - '*.md'
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}