Update php version in travis

.travis.yml

@@ -1,6 +1,6 @@
 language: php
 php:
-  - 7.1
+  - 7.2
 
 cache:
   directories:

.travis/install.sh

@@ -1,20 +1,20 @@
 #!/bin/bash
 
 # Install some custom requirements on Linux
-if [ $(phantomjs --version) != '2.1.1' ]; then
+if [[ $(phantomjs --version) != '2.1.1' ]]; then
 
     echo "Installing phantomjs ...";
 
     rm -rf $PWD/travis_phantomjs;
     mkdir -p $PWD/travis_phantomjs;
 fi
 
-if [ $(phantomjs --version) != '2.1.1' ]; then
+if [[ $(phantomjs --version) != '2.1.1' ]]; then
 
     wget https://assets.membergetmember.co/software/phantomjs-2.1.1-linux-x86_64.tar.bz2 -O $PWD/travis_phantomjs/phantomjs-2.1.1-linux-x86_64.tar.bz2;
 fi
 
-if [ $(phantomjs --version) != '2.1.1' ]; then
+if [[ $(phantomjs --version) != '2.1.1' ]]; then
 
     tar -xvf $PWD/travis_phantomjs/phantomjs-2.1.1-linux-x86_64.tar.bz2 -C $PWD/travis_phantomjs;
 fi