fix: start docker as service

.github/workflows/unittest.yml

@@ -14,6 +14,11 @@ env:
 jobs:
   py-httprunner:
     runs-on: ${{ matrix.os }}
+    services:
+      service-httpbin:
+        image: kennethreitz/httpbin
+        ports:
+           - 80:80
     strategy:
       fail-fast: false
       max-parallel: 12
@@ -28,10 +33,6 @@ jobs:
       with:
         python-version: ${{ matrix.python-version }}
         architecture: x64
-    - name: start httpbin server with docker
-      run: |
-        docker pull kennethreitz/httpbin
-        docker run -p 80:80 kennethreitz/httpbin
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip