Update travis.yml to use php 8

Signed-off-by: Sem Schilder <[email protected]>

.travis.yml

@@ -12,38 +12,15 @@ env:
 matrix:
   fast_finish: true
   include:
-    - php: 5.6
-      env:
-        - DEPS=lowest
-    - php: 5.6
-      env:
-        - DEPS=latest
-    - php: 7
-      env:
-        - DEPS=lowest
-    - php: 7
-      env:
-        - DEPS=latest
-    - php: 7.1
-      env:
-        - DEPS=lowest
-    - php: 7.1
-      env:
-        - DEPS=latest
-        - CS_CHECK=true
-        - TEST_COVERAGE=true
-    - php: 7.2
-      env:
-        - DEPS=lowest
-    - php: 7.2
-      env:
-        - DEPS=latest
     - php: 7.3
       env:
         - DEPS=lowest
     - php: 7.3
       env:
         - DEPS=latest
+    - php: 8.0
+      env:
+        - COMPOSER_ARGS="--no-interaction --ignore-platform-reqs"
 
 before_install:
   - if [[ $TEST_COVERAGE != 'true' ]]; then phpenv config-rm xdebug.ini || return 0 ; fi