Exclude tests on PHP 7.4 for not supported PHPUnit versions (<= 8.1)

Author: michalbundyra

.travis.yml

@@ -1,7 +1,5 @@
 language: php
 
-sudo: false
-
 cache:
   directories:
     - $HOME/.composer/cache
@@ -38,6 +36,33 @@ php:
 matrix:
   fast_finish: true
   exclude:
+    - php: 7.4
+      env: PHPUNIT_VERSION=~8.1.0
+    - php: 7.4
+      env: PHPUNIT_VERSION=~8.0.0
+    - php: 7.4
+      env: PHPUNIT_VERSION=~7.4.0
+    - php: 7.4
+      env: PHPUNIT_VERSION=~7.3.0
+    - php: 7.4
+      env: PHPUNIT_VERSION=~7.2.0
+    - php: 7.4
+      env: PHPUNIT_VERSION=~7.1.0
+    - php: 7.4
+      env: PHPUNIT_VERSION=~7.0.0
+    - php: 7.4
+      env: PHPUNIT_VERSION=~6.5.0
+    - php: 7.4
+      env: PHPUNIT_VERSION=~6.4.0
+    - php: 7.4
+      env: PHPUNIT_VERSION=~6.3.0
+    - php: 7.4
+      env: PHPUNIT_VERSION=~6.2.0
+    - php: 7.4
+      env: PHPUNIT_VERSION=~6.1.0
+    - php: 7.4
+      env: PHPUNIT_VERSION=~6.0.0
+
     - php: 7.2
       env: PHPUNIT_VERSION=dev-master
     - php: 7.2
@@ -58,6 +83,7 @@ matrix:
       env: PHPUNIT_VERSION=~8.1.0
     - php: 7.1
       env: PHPUNIT_VERSION=~8.0.0
+
     - php: 7
       env: PHPUNIT_VERSION=dev-master
     - php: 7