Remove SilverStripe 4.0-4.2 from Travis builds

.travis.yml

@@ -17,13 +17,13 @@ env:
 matrix:
   include:
     - php: 5.6
-      env: DB=MYSQL INSTALLER_VERSION=4.0.x-dev PHPCS_TEST=1 PHPUNIT_TEST=1
+      env: DB=MYSQL INSTALLER_VERSION=4.3.x-dev PHPCS_TEST=1 PHPUNIT_TEST=1
     - php: 7.0
-      env: DB=PGSQL INSTALLER_VERSION=4.1.x-dev PHPUNIT_TEST=1
+      env: DB=PGSQL INSTALLER_VERSION=4.3.x-dev PHPUNIT_TEST=1
     - php: 7.1
-      env: DB=MYSQL INSTALLER_VERSION=4.1.x-dev BEHAT_TEST=1
+      env: DB=MYSQL INSTALLER_VERSION=4.3.x-dev BEHAT_TEST=1
     - php: 7.2
-      env: DB=MYSQL INSTALLER_VERSION=4.2.x-dev PHPUNIT_COVERAGE_TEST=1
+      env: DB=MYSQL INSTALLER_VERSION=4.3.x-dev PHPUNIT_COVERAGE_TEST=1
     - php: 7.2
       env: DB=MYSQL INSTALLER_VERSION=4.x-dev BEHAT_TEST=1
 
@@ -39,7 +39,7 @@ before_script:
   # Install composer
   - composer validate
   - composer require silverstripe/installer:"$INSTALLER_VERSION" silverstripe/recipe-testing:^1 --no-update
-  - if [[ $DB == PGSQL ]]; then composer require --no-update silverstripe/postgresql:2.0.x-dev; fi
+  - if [[ $DB == PGSQL ]]; then composer require --no-update silverstripe/postgresql:2.1.x-dev; fi
   - composer install --prefer-source --no-interaction --no-progress --no-suggest --optimize-autoloader --verbose --profile
 
   # Behat bootstrapping