Updated build matrix for Travis-CI according to the changes in composer.json

Fixes #2994.

Author: morozov

.travis.yml

@@ -227,7 +227,7 @@ jobs:
 
     - stage: Pull request coding standard
       if: type = pull_request
-      php: 7.1
+      php: 7.2
       script:
         - |
           if [ $TRAVIS_BRANCH != "master" ]; then
@@ -240,6 +240,6 @@ jobs:
 
     - stage: Coding standard
       if: NOT type = pull_request
-      php: 7.1
+      php: 7.2
       script:
         - ./vendor/bin/phpcs