Update MySQL in TravisCI script

Author: ivanvermeyen

.travis.yml

@@ -8,7 +8,7 @@ php:
 services:
   - mysql
 
-sudo: false
+sudo: true
 
 cache:
   directories:
@@ -17,6 +17,12 @@ cache:
 before_script:
   - travis_retry composer self-update
   - travis_retry composer update --no-interaction
+  - echo mysql-apt-config mysql-apt-config/select-server select mysql-5.7 | sudo debconf-set-selections
+  - wget https://dev.mysql.com/get/mysql-apt-config_0.7.3-1_all.deb
+  - sudo dpkg --install mysql-apt-config_0.7.3-1_all.deb
+  - sudo apt-get update -q
+  - sudo apt-get install -q -y --allow-unauthenticated -o Dpkg::Options::=--force-confnew mysql-server
+  - sudo mysql_upgrade
   - mysql -e "create database IF NOT EXISTS testing;" -uroot;
 
 script: