build: Fix coverage concurrency issues

Author: untitaker

.travis.yml

@@ -58,8 +58,8 @@ install:
 
 script:
   - coverage erase
-  - ./scripts/runtox.sh '' --cov=sentry_sdk --cov-append --cov-report= --cov-branch
-  - codecov
+  - ./scripts/runtox.sh '' --cov=sentry_sdk --cov-report= --cov-branch
+  - codecov --file .coverage*
 
 notifications:
   webhooks:

tox.ini

@@ -113,6 +113,8 @@ setenv =
     rq: TESTPATH=tests/integrations/rq
     aiohttp: TESTPATH=tests/integrations/aiohttp
     tornado: TESTPATH=tests/integrations/tornado
+
+    COVERAGE_FILE=.coverage-{envname}
 passenv =
     AWS_ACCESS_KEY_ID
     AWS_SECRET_ACCESS_KEY