fix: only upload coverage report on latest php version

Author: pimlie

.travis.yml

@@ -11,4 +11,4 @@ script:
   - if [[ "${TRAVIS_PHP_VERSION:0:3}" != "7.2" ]]; then composer test:standard; fi
   - if [[ "${TRAVIS_PHP_VERSION:0:3}" == "7.2" ]]; then composer test:all -- --coverage-clover clover.xml; fi
 after_success:
-  - travis_retry php vendor/bin/php-coveralls -v --coverage_clover clover.xml --json_path coveralls-upload.json
+  - if [[ "${TRAVIS_PHP_VERSION:0:3}" == "7.2" ]]; then travis_retry php vendor/bin/php-coveralls -v --coverage_clover clover.xml --json_path coveralls-upload.json; fi