add php 8.0 to matrix

Signed-off-by: Matthew Peveler <matt.peveler@popsql.com>

Author: MasterOdin

.github/workflows/test.yml

@@ -10,7 +10,7 @@ jobs:
 
     strategy:
       matrix:
-        php-version: ['5.6', '7.0', '7.1', '7.2', '7.3', '7.4']
+        php-version: ['5.6', '7.0', '7.1', '7.2', '7.3', '7.4', '8.0']
 
     steps:
     - uses: actions/checkout@v2