Merge pull request #1818 from ampproject/1813-php73-for-travis

Run tests using PHP 7.3 on Travis CI

.travis.yml

@@ -34,7 +34,7 @@ after_script:
 jobs:
   include:
     - stage: test
-      php: "7.2"
+      php: "7.3"
       env: WP_VERSION=5.0
     - php: "5.4"
       env: WP_VERSION=4.9    DEV_LIB_SKIP=composer,phpcs
@@ -48,6 +48,8 @@ jobs:
       env: WP_VERSION=latest DEV_LIB_SKIP=phpcs
     - php: "7.1"
       env: WP_VERSION=latest DEV_LIB_SKIP=phpcs
+    - php: "7.2"
+      env: WP_VERSION=latest DEV_LIB_SKIP=phpcs
     - stage: deploy
       if: type = push AND fork = false AND ( branch =~ ^[a-z][a-z0-9-]{0,10}$ OR branch =~ ^[0-9]+\.[0-9]+$ ) AND NOT branch IN ( live, test, dev, settings, team, support, debug, multidev, files, tags, billing )
       php: "7.1"