update travis to use codecov instead of coveralls

Author: saimaz

.travis.yml

@@ -23,4 +23,4 @@ script:
   - vendor/bin/phpunit --coverage-clover=coverage.clover
   - vendor/bin/phpcs -p --standard=PSR2 --ignore=vendor/,Tests/app/,var/cache ./
 after_script:
-  - travis_retry php vendor/bin/coveralls
+  - travis_retry bash <(curl -s https://codecov.io/bash)

README.md

@@ -24,6 +24,7 @@ is the preferred and recommended way to ask questions about ONGR bundles and lib
 
 [![Build Status](https://travis-ci.org/ongr-io/ElasticsearchBundle.svg?branch=master)](https://travis-ci.org/ongr-io/ElasticsearchBundle)
 [![Latest Stable Version](https://poser.pugx.org/ongr/elasticsearch-bundle/v/stable)](https://packagist.org/packages/ongr/elasticsearch-bundle)
+[![codecov](https://codecov.io/gh/ongr-io/ElasticsearchBundle/branch/master/graph/badge.svg)](https://codecov.io/gh/ongr-io/ElasticsearchBundle)
 [![Total Downloads](https://poser.pugx.org/ongr/elasticsearch-bundle/downloads)](https://packagist.org/packages/ongr/elasticsearch-bundle)
 [![Scrutinizer Code Quality](https://scrutinizer-ci.com/g/ongr-io/ElasticsearchBundle/badges/quality-score.png?b=master)](https://scrutinizer-ci.com/g/ongr-io/ElasticsearchBundle/?branch=master)
 
@@ -32,7 +33,8 @@ is the preferred and recommended way to ask questions about ONGR bundles and lib
 
 | Elasticsearch version | ElasticsearchBundle version      |
 | --------------------- | -------------------------------- |
-| >= 6.0                | ~6.x                             |
+| >= 7.0                | ~7.x                             |
+| >= 6.0, < 7.0         | ~6.x                             |
 | >= 5.0, < 5.0         | ~5.x, ~6.x (indexes with 1 type) |
 | >= 2.0, < 5.0         | >=1.0, < 5.0                     |
 | >= 1.0, < 2.0         | >= 0.10, < 1.0                   |