ci: Travis: skip coverage with cron runs

The current commit on features has 50+ uploads already:
https://codecov.io/gh/pytest-dev/pytest/commit/c7bbb2a78873a63b9df9df08f8dc77cde30debd3/build

Author: blueyed

.travis.yml

@@ -86,6 +86,11 @@ jobs:
           repo: pytest-dev/pytest
 
 before_script:
+  - |
+    # Do not (re-)upload coverage with cron runs.
+    if [[ "$TRAVIS_EVENT_TYPE" = cron ]]; then
+      PYTEST_COVERAGE=0
+    fi
   - |
     if [[ "$PYTEST_COVERAGE" = 1 ]]; then
       export COVERAGE_FILE="$PWD/.coverage"