Add test by php7.3

Author: egs33

.circleci/config.yml

@@ -40,6 +40,9 @@ workflows:
       - test:
           name: "test-php7.2"
           php-version: "7.2"
+      - test:
+          name: "test-php7.3"
+          php-version: "7.3"
       - test:
           name: "test-php7.1-prefer_lowest"
           php-version: "7.1"
@@ -48,3 +51,7 @@ workflows:
           name: "test-php7.2-prefer_lowest"
           php-version: "7.2"
           composer_arguments: "--prefer-lowest"
+      - test:
+          name: "test-php7.3-prefer_lowest"
+          php-version: "7.3"
+          composer_arguments: "--prefer-lowest"