bump travis php version

jszobody · jszobody · commit 1fbee80da7d8 · 2020-01-22T20:47:04.000-05:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,8 +1,7 @@
 language: php
 
 php:
-  - 5.6
-  - 7.2
+  - 7.3
 
 before_script:
   - travis_retry composer self-update
