Update .travis.yml

.travis.yml

@@ -2,6 +2,10 @@ language: php
 
 dist: trusty
 
+sudo: required
+
+group: deprecated-2017Q4
+
 cache:
   directories:
     - $HOME/.composer/cache/files
@@ -15,7 +19,7 @@ addons:
 env:
   global:
     - TRAVIS_NODE_VERSION="6"
-    - COMPOSER_ROOT_VERSION="4.x-dev"
+    - COMPOSER_ROOT_VERSION="4.1.x-dev"
     - DISPLAY=":99"
     - XVFBARGS=":99 -ac -screen 0 1024x768x16"
     - SS_BASE_URL="http://localhost:8080/"
@@ -44,12 +48,10 @@ before_script:
 
 # Install composer dependencies
   - composer validate
-  - composer install --prefer-dist
-  - composer require --prefer-dist --no-update silverstripe/recipe-cms:1.1.x-dev
-  - composer update
-  - if [[ $DB == PGSQL ]]; then composer require silverstripe/postgresql:2.1.x-dev --prefer-dist; fi
-  - if [[ $DB == SQLITE ]]; then composer require silverstripe/sqlite3:2.1.x-dev --prefer-dist; fi
+  - composer require --no-update silverstripe/recipe-cms:1.1.x-dev
+  - if [[ $DB == PGSQL ]]; then composer require --no-update silverstripe/postgresql:2.0.x-dev; fi
   - if [[ $PHPCS_TEST ]]; then composer global require squizlabs/php_codesniffer:^3 --prefer-dist --no-interaction --no-progress --no-suggest -o; fi
+  - composer install --prefer-source --no-interaction --no-progress --no-suggest --optimize-autoloader --verbose --profile
 
 # Install NPM dependencies
   - if [[ $NPM_TEST ]]; then nvm install $TRAVIS_NODE_VERSION && nvm use $TRAVIS_NODE_VERSION && npm install -g yarn && yarn install --network-concurrency 1 && yarn run build; fi