Switch master php to nightly php on travis

sergeyklay · sergeyklay · commit b393211a34da · 2019-04-24T20:21:20.000+03:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,6 +1,6 @@
 language: php
 php:
-  - 'master'
+  - 'nightly'
   - '7.3'
   - '7.2'
   - '7.1'
