cleaning up references to failing php versions

Author: SignpostMarv

Diff for: .travis.yml

@@ -6,8 +6,6 @@ php:
   - 5.6
   - 7.0
   - 7.1
-  - 7.2
-  - 7.3
 cache:
   directories:
     - ./vendor/
@@ -17,5 +15,3 @@ script:
   - composer run tests
 matrix:
   fast_finish: true
-  allow_failures:
-    - php: hhvm