ci: Skip Coveralls submission if COVERALLS_REPO_TOKEN env. var is empty

Author: jcfr

.circleci/config.yml

@@ -159,7 +159,12 @@ jobs:
     steps:
       - run:
           name: Complete Coveralls
-          command: curl --fail https://coveralls.io/webhook?repo_token=$COVERALLS_REPO_TOKEN -d "payload[build_num]=$CIRCLE_WORKFLOW_ID&payload[status]=done"
+          command: |
+            if [[ "$COVERALLS_REPO_TOKEN" != "" ]]; then
+              curl --fail https://coveralls.io/webhook?repo_token=$COVERALLS_REPO_TOKEN -d "payload[build_num]=$CIRCLE_WORKFLOW_ID&payload[status]=done"
+            else
+              echo "Skipping Coveralls"
+            fi
 
 workflows:
   version: 2