ci: Upgrade travis.yml to Xenial to get Mysql 5.7 support

Author: liqueurdetoile

.travis.yml

@@ -1,4 +1,4 @@
-dist: trusty
+dist: xenial
 sudo: required
 
 env:
@@ -15,14 +15,6 @@ php:
 services:
   - mysql
 
-addons:
-  apt:
-    sources:
-      - mysql-5.7-trusty
-    packages:
-      - mysql-server
-      - mysql-client
-
 before_install:
   #- sudo mysql -e "use mysql; update user set authentication_string=PASSWORD('datpassword') where User='root'; update user set plugin='mysql_native_password';FLUSH PRIVILEGES;"
   #- sudo mysql_upgrade
@@ -46,7 +38,7 @@ script:
   - composer phpstan
 
 after_success:
-# Submit coverage report to Coveralls servers, see .coveralls.yml
+# Submit coverage report to Coveralls servers, see .coveral ls.yml
  - travis_retry php coveralls.phar -v
 
 #after_failure: