Merge coverage outputs.

Author: onurtemizkan

plugins/node/opentelemetry-instrumentation-winston/package.json

@@ -9,7 +9,7 @@
     "test": "npm run test-v1-v2 && npm run test-v3 && nyc merge .nyc_output ./coverage/coverage-final.json",
     "test-v1-v2": "tav winston 2.4.7 npm run test-run",
     "test-v3": "tav winston 3.17.0 npm run test-run",
-    "test-run": "nyc mocha 'test/**/*.test.ts'",
+    "test-run": "nyc --no-clean mocha 'test/**/*.test.ts'",
     "test-all-versions": "tav",
     "tdd": "npm run test-run -- --watch-extensions ts --watch",
     "clean": "rimraf build/*",