Update the version of PHP used in tests. (#4415)

.travis.yml

@@ -31,43 +31,43 @@ env:
 matrix:
   include:
     # D9.0.x
-    - php: 7.3
+    - php: 7.4
       env: 'UNISH_DRUPAL_MAJOR_VERSION=9 UNISH_DRUPAL_MINOR_VERSION=0.x-dev'
 
     # D8.9.x
-    - php: 7.3
+    - php: 7.4
       env: 'UNISH_DRUPAL_MAJOR_VERSION=8 UNISH_DRUPAL_MINOR_VERSION=9.x-dev'
 
     # D8.8.x
-    - php: 7.2
+    - php: 7.3
       env: 'UNISH_DRUPAL_MAJOR_VERSION=8 UNISH_DRUPAL_MINOR_VERSION=8.5'
 
     # D8.7.x
-    - php: 7.0
+    - php: 7.2
       env: 'UNISH_DRUPAL_MAJOR_VERSION=8 UNISH_DRUPAL_MINOR_VERSION=7.12'
 
     # D8.6.x
-    - php: 7.0
+    - php: 7.1
       env: 'UNISH_DRUPAL_MAJOR_VERSION=8 UNISH_DRUPAL_MINOR_VERSION=6.18'
 
     # D8.5.x
-    - php: 7.0
+    - php: 7.1
       env: 'UNISH_DRUPAL_MAJOR_VERSION=8 UNISH_DRUPAL_MINOR_VERSION=5.15'
 
     # D8.4.x
-    - php: 7.0
+    - php: 7.1
       env: 'UNISH_DRUPAL_MAJOR_VERSION=8 UNISH_DRUPAL_MINOR_VERSION=4.8 PHPUNIT_ARGS=--group=commands'
 
     # D8.3.x
-    - php: 7.0
+    - php: 7.1
       env: 'UNISH_DRUPAL_MAJOR_VERSION=8 UNISH_DRUPAL_MINOR_VERSION=3.9 PHPUNIT_ARGS=--group=commands'
 
     # D8.2.x
     - php: 7.0
       env: 'UNISH_DRUPAL_MAJOR_VERSION=8 UNISH_DRUPAL_MINOR_VERSION=2.8 PHPUNIT_ARGS=--group=commands'
 
     # D7
-    - php: 7.0
+    - php: 7.1
       env: 'UNISH_DRUPAL_MAJOR_VERSION=7'
 
     # D7