try to fix coverage.groovy bug

Former-commit-id: ff3e85bc41bc7649b3c261c2ba614da1fc128b96

ci/jenkins/jenkinsfile/coverage.groovy

@@ -2,7 +2,7 @@ timeout(time: 60, unit: 'MINUTES') {
     dir ("ci/jenkins/scripts") {
         sh "./coverage.sh -o /opt/milvus -u root -p 123456 -t \$POD_IP"
         // Set some env variables so codecov detection script works correctly
-        sh 'bash <(curl -s https://codecov.io/bash) -f output_new.info || echo "Codecov did not collect coverage reports"'
+        sh "bash <(curl -s https://codecov.io/bash) -f output_new.info || echo 'Codecov did not collect coverage reports'"
     }
 }