Use vendor phpunit

Author: bcrowe

.travis.yml

@@ -17,7 +17,7 @@ before_script:
   - composer install --prefer-dist --no-interaction
 
 script:
-  - sh -c "if [ '$RUN_TESTS' = '1' ]; then phpunit --coverage-text --coverage-clover=coverage.clover; fi"
+  - sh -c "if [ '$RUN_TESTS' = '1' ]; then vendor/bin/phpunit --coverage-text --coverage-clover=coverage.clover; fi"
   - sh -c "if [ '$PHPCS' = '1' ]; then vendor/bin/phpcs -p -n --extensions=php --standard=psr2 ./src ./tests; fi"
 
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