Fixes Travis CI configuration

- reorder PHPUnit versions that we run the latests first
- 7.4snapshot instead of 7.4-snapshot

Author: michalbundyra

.travis.yml

@@ -8,24 +8,24 @@ cache:
 
 env:
   - PHPUNIT_VERSION=dev-master
-  - PHPUNIT_VERSION=~6.0.0
-  - PHPUNIT_VERSION=~6.1.0
-  - PHPUNIT_VERSION=~6.2.0
-  - PHPUNIT_VERSION=~6.3.0
-  - PHPUNIT_VERSION=~6.4.0
-  - PHPUNIT_VERSION=~6.5.0
-  - PHPUNIT_VERSION=~7.0.0
-  - PHPUNIT_VERSION=~7.1.0
-  - PHPUNIT_VERSION=~7.2.0
-  - PHPUNIT_VERSION=~7.3.0
-  - PHPUNIT_VERSION=~7.4.0
-  - PHPUNIT_VERSION=~7.5.0
-  - PHPUNIT_VERSION=~8.0.0
-  - PHPUNIT_VERSION=~8.1.0
   - PHPUNIT_VERSION=~8.2.0
+  - PHPUNIT_VERSION=~8.1.0
+  - PHPUNIT_VERSION=~8.0.0
+  - PHPUNIT_VERSION=~7.5.0
+  - PHPUNIT_VERSION=~7.4.0
+  - PHPUNIT_VERSION=~7.3.0
+  - PHPUNIT_VERSION=~7.2.0
+  - PHPUNIT_VERSION=~7.1.0
+  - PHPUNIT_VERSION=~7.0.0
+  - PHPUNIT_VERSION=~6.5.0
+  - PHPUNIT_VERSION=~6.4.0
+  - PHPUNIT_VERSION=~6.3.0
+  - PHPUNIT_VERSION=~6.2.0
+  - PHPUNIT_VERSION=~6.1.0
+  - PHPUNIT_VERSION=~6.0.0
 
 php:
-  - 7.4-snapshot
+  - 7.4snapshot
   - 7.3
   - 7.2
   - 7.1
@@ -63,7 +63,7 @@ matrix:
     - php: 7
       env: PHPUNIT_VERSION=~7.0.0
   allow_failures:
-    - php: 7.4-snapshot
+    - php: 7.4snapshot
     - env: PHPUNIT_VERSION=dev-master
 
 install: