Run unit tests on PHP8

Author: phil-davis

.travis.yml

@@ -25,6 +25,14 @@ env:
 
 matrix:
   include:
+    - name: 'PHP8'
+      dist: focal
+      php: nightly
+      addons:
+        postgresql: '12'
+      env:
+        - RUN_PHPCSFIXER="FALSE"
+        - REPORT_COVERAGE="FALSE"
     - name: 'PHPStan'
       php: 7.4
       env:

composer.json

@@ -14,7 +14,7 @@
         }
     ],
     "require": {
-        "php": "^7.1.0",
+        "php": "^7.1.0 || ^8.0",
         "sabre/vobject": "^4.2.1",
         "sabre/event" : "^5.0",
         "sabre/xml"  : "^2.0.1",