Update travis.

Signed-off-by: Mior Muhammad Zaki <crynobone@gmail.com>

.travis.yml

@@ -10,12 +10,12 @@ env:
     - setup=basic
     - coverage=no
   matrix:
-    - laravel=5.8.*
-    - laravel=dev-master
-    - setup=stable laravel=5.8.*
-    - setup=stable laravel=dev-master
-    - setup=lowest laravel=5.8.*
-    - setup=lowest laravel=dev-master
+    - laravel=^5.8
+    - laravel=^6.0
+    - setup=stable laravel=^5.8
+    - setup=stable laravel=^6.0
+    - setup=lowest laravel=^5.8
+    - setup=lowest laravel=^6.0
 
 before_install:
   - travis_retry composer self-update
@@ -37,13 +37,13 @@ after_script:
 matrix:
   include:
     - php: 7.1
-      env: laravel=5.8.*
+      env: laravel=^5.8
     - php: 7.1
-      env: setup=stable laravel=5.8.*
+      env: setup=stable laravel=^5.8
     - php: 7.1
-      env: setup=lowest laravel=5.8.*
+      env: setup=lowest laravel=^5.8
     - php: 7.1
-      env: setup=coveralls coverage=yes laravel=5.8.*
+      env: setup=coveralls coverage=yes laravel=^5.8
   allow_failures:
-    - env: setup=coveralls coverage=yes laravel=5.8.*
+    - env: setup=coveralls coverage=yes laravel=^5.8
   fast_finish: true