[skip ci] Adjust the coverage index of project and patch to 80% (#7883)

Signed-off-by: Nwangting0128 <ting.wang@zilliz.com>

.github/mergify.yml

@@ -6,6 +6,7 @@ pull_request_rules:
       - "status-success=Build and test AMD64 Ubuntu 18.04"
       - "status-success=continuous-integration/jenkins/pr-merge"
       - "status-success=codecov/patch"
+      - "status-success=codecov/project"
     actions:
       label:
         add:

codecov.yml

@@ -11,12 +11,13 @@ coverage:
   status:
     project:
       default:
+        target: 80%
         threshold: 0% #Allow the coverage to drop by threshold%, and posting a success status.
         branches:
           - master
     patch:
       default:
-        target: 70%
+        target: 80%
         threshold: 0%
         branches:
           - master