Run unit tests on PHP8

Author: phil-davis

.travis.yml

@@ -16,6 +16,12 @@ env:
 
 matrix:
   include:
+    - name: 'PHP8'
+      dist: focal
+      php: nightly
+      env:
+        - RUN_PHPCSFIXER="FALSE"
+        - REPORT_COVERAGE="FALSE"
     - name: 'PHPStan'
       php: 7.4
       env:

composer.json

@@ -10,7 +10,7 @@
     "homepage": "http://sabre.io/dav/",
     "license": "BSD-3-Clause",
     "require": {
-        "php"       : "^7.1",
+        "php"       : "^7.1 || ^8.0",
         "sabre/xml" : "^2.0"
     },
     "authors": [