updated TEST_YII_VERSION

- related yiisoft/yii2#17708

Author: schmunk42

.travis.yml

@@ -24,7 +24,7 @@ matrix:
     - env: PHP_BASE_IMAGE_VERSION=7.0-apache DOCKERFILE_FLAVOUR=debian X_LEGACY_GD_LIB=1
 
 before_install:
-  - export TEST_YII_VERSION=83055dcc3347f0f9a30afa448339141f2f9ec7f7
+  - export TEST_YII_VERSION=a777c2e8f69dc753f8a945b1dd54bbaaa1e9e66c
   - export DOCKER_COMPOSE_VERSION=1.16.1
   - export PHP_IMAGE_NAME=yiisoftware/yii2-php
   - if [ -n "$TRAVIS_TAG" ]; then export PHP_IMAGE_VERSION_SUFFIX=-${TRAVIS_TAG}; fi