Bump Travis CI PHP version.

Author: danepowell

.travis.yml

@@ -5,7 +5,9 @@ os: linux
 
 version: ~> 1.0
 
-php: "7.2"
+php:
+  - "7.2"
+  - "7.4"
 
 addons:
   chrome: stable
@@ -29,7 +31,7 @@ env:
     # Custom configuration.
     - COMPOSER_BIN=$TRAVIS_BUILD_DIR/vendor/bin
     - BLT_DIR=$TRAVIS_BUILD_DIR
-    - DRUPAL_CORE_HEAD=8.8.x-dev
+    - DRUPAL_CORE_HEAD=8.9.x-dev
     # Change to 1 to debug failed tests.
     - BLT_PRINT_COMMAND_OUTPUT=0
 
@@ -46,6 +48,7 @@ jobs:
     - { name: "Integrated test w/ dev package versions & next minor dev version of Drupal core", env: ORCA_JOB=CORE_NEXT }
     # Custom jobs.
     - env: DRUPAL_CORE_VERSION=default PHPUNIT_EXCLUDE_GROUP='drupal,requires-vm'
+    - { env: DRUPAL_CORE_VERSION=default PHPUNIT_EXCLUDE_GROUP='drupal,requires-vm', php: "7.4"}
     - env: DRUPAL_CORE_VERSION=default PHPUNIT_GROUP='drupal'
     - env: DRUPAL_CORE_VERSION=$DRUPAL_CORE_HEAD
   allow_failures: