Allow php nightlies to fail

SMillerDev · SMillerDev · commit 58f80a9564d7 · 2018-02-20T14:13:02.000+01:00
diff --git a/.travis.yml b/.travis.yml
@@ -5,6 +5,11 @@ php:
 - '7.1'
 - '7.2'
 - nightly
+env: # important!
+matrix:
+  allow_failures:
+  - php: nightly
+
 before_script:
 - travis_retry composer self-update
 - travis_retry composer install --no-interaction --prefer-source --dev
