chore: rename unit test job (openobserve#7032)

Author: oasisk

.github/workflows/unit-tests.yml

@@ -17,7 +17,7 @@ env:
   ZO_RESULT_CACHE_ENABLED: true
 
 jobs:
-  build:
+  unit_tests:
 
     runs-on: 
       labels: ubicloud-standard-8
@@ -52,4 +52,4 @@ jobs:
 
       - name: Run unit tests
         run: ./coverage.sh
-      
+