Merge tag '3.1.11' into develop

Tagging hotfix 3.1.11 3.1.11

.gitattributes

@@ -0,0 +1,6 @@
+.gitattributes export-ignore
+.github export-ignore
+.gitignore export-ignore
+.travis.yml export-ignore
+phpunit.xml export-ignore
+tests export-ignore

.travis.yml

@@ -5,7 +5,7 @@ php:
   - '7.0'
   - '7.1'
   - '7.2'
-  - nightly
+  - '7.3'
 
 # cache vendor dirs
 cache:
@@ -15,7 +15,7 @@ cache:
 
 install:
   - travis_retry composer self-update && composer --version
-  - travis_retry composer install --prefer-dist --no-interaction
+  - travis_retry composer install --no-interaction
 
 before_script:
   - sudo apt-get install p7zip-full