Use trusty distro in Travis builds and update tested SilverStripe ver…

…sions

.travis.yml

@@ -1,16 +1,18 @@
 language: php
 
+dist: trusty
+
 matrix:
   include:
     - php: 5.6
-      env: DB=MYSQL RECIPE_VERSION=1.0.x-dev PHPCS_TEST=1 PHPUNIT_TEST=1
+      env: DB=MYSQL RECIPE_VERSION=4.2.x-dev PHPCS_TEST=1 PHPUNIT_TEST=1
     - php: 7.0
-      env: DB=MYSQL RECIPE_VERSION=1.1.x-dev PHPUNIT_TEST=1
-    - php: 7.1
-      env: DB=MYSQL RECIPE_VERSION=4.2.x-dev PHPUNIT_COVERAGE_TEST=1
-    - php: 7.2
       env: DB=MYSQL RECIPE_VERSION=4.3.x-dev PHPUNIT_TEST=1
+    - php: 7.1
+      env: DB=MYSQL RECIPE_VERSION=4.4.x-dev PHPUNIT_COVERAGE_TEST=1
     - php: 7.2
+      env: DB=MYSQL RECIPE_VERSION=4.5.x-dev PHPUNIT_TEST=1
+    - php: 7.3
       env: DB=MYSQL RECIPE_VERSION=4.x-dev PHPUNIT_TEST=1
 
 before_script: