Add Docker build badge to README.md

Change-Id: I8577bed7294511896338ac5a6db397b0fd03ee0c
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ae09443..fdf76cb 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -2,10 +2,14 @@
 on:
   push:
     paths-ignore:
-      - 'docs/**'
       - '*.conf.sample*'
-      - '*.md'
+      - 'Dockerfile'
+      - '.dockerignore'
+      - 'docs/**'
+      - '.editorconfig'
+      - '.gitignore'
       - '.mailmap'
+      - '*.md'
   workflow_dispatch:
 
 permissions: {}