Use PHP 7.3 alias.

.travis.yml

@@ -5,11 +5,9 @@ php:
   - 5.6
   - 7.1
   - 7.2
-  - 7.3.0RC1
+  - 7.3
 
-sudo: required
-
-dist: xenial
+dist: trusty
 
 env:
   matrix:
@@ -26,9 +24,6 @@ services:
   - mysql
 
 addons:
-  apt:
-    packages:
-      - libzip4
   postgresql: "9.4"
 
 cache:
@@ -48,7 +43,7 @@ matrix:
 
 before_install:
   - echo cakephp version && tail -1 VERSION.txt
-  - if [[ ${TRAVIS_PHP_VERSION} != "7.3.0RC1" ]]; then phpenv config-rm xdebug.ini; fi
+  - if [[ ${TRAVIS_PHP_VERSION} != "7.3" ]]; then phpenv config-rm xdebug.ini; fi
 
   - if [ $DB = 'mysql' ]; then mysql -u root -e 'CREATE DATABASE cakephp_test;'; fi
   - if [ $DB = 'mysql' ]; then mysql -u root -e 'CREATE DATABASE cakephp_test2;'; fi
@@ -60,7 +55,7 @@ before_install:
 
   - if [[ $DEFAULT = 1 || $PHPSTAN = 1 ]] ; then pecl channel-update pecl.php.net; fi;
   - |
-      if [[ ${TRAVIS_PHP_VERSION} != "7.3.0RC1" && ${TRAVIS_PHP_VERSION} != "5.6" && ($DEFAULT = 1 || $PHPSTAN = 1) ]]; then
+      if [[ ${TRAVIS_PHP_VERSION} != "7.3" && ${TRAVIS_PHP_VERSION} != "5.6" && ($DEFAULT = 1 || $PHPSTAN = 1) ]]; then
         echo 'extension = memcached.so' >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini;
       fi
   - if [[ $DEFAULT = 1 || $PHPSTAN = 1 ]] ; then echo 'extension = redis.so' >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini; fi