Fix indentation in workflow yaml for testing khoj backend

Author: debanjum

.github/workflows/test.yml

@@ -28,10 +28,10 @@ jobs:
       fail-fast: false
       matrix:
         python_version:
-          - 3.8
-          - 3.9
-          - 3.10
-     steps:
+          - '3.8'
+          - '3.9'
+          - '3.10'
+    steps:
       - uses: actions/checkout@v3
 
       - name: Set up Python