travis: update configuration to enable mysql & postgresql correctly

.travis.yml

@@ -6,17 +6,18 @@ php:
     - 7.3
     - 7.4snapshot
 
+services:
+    - mysql
+    - postgresql
+
 env:
-  matrix:
-    - dependencies=lowest
-    - dependencies=highest
+    matrix:
+        - dependencies=lowest
+        - dependencies=highest
 
 matrix:
     fast_finish: true
 
-addons:
-  postgresql: "9.6"
-
 cache:
     directories:
         - $HOME/.composer/cache
@@ -48,10 +49,10 @@ script:
 
 after_script:
     - if [ "$TRAVIS_PHP_VERSION" == "7.2" ]; then
-      wget https://github.com/satooshi/php-coveralls/releases/download/v2.0.0/php-coveralls.phar
-      && php php-coveralls.phar --verbose --config tests/.coveralls.yml
-      || true;
-      fi
+        wget https://github.com/satooshi/php-coveralls/releases/download/v2.0.0/php-coveralls.phar
+        && php php-coveralls.phar --verbose --config tests/.coveralls.yml
+        || true;
+        fi
 
 after_failure:
     # Print *.actual content & log content