Update Travis config

The problem when the project uses symfony/framework-bundle.
composer require --ignore-platform-reqs install  psr/cache 2.0, his support only PHP 8, but in Travis use PHP 7.4.
1) Remove --ignore-platform-reqs 
or 
2) Use in build PHP 8.0

PHP 8.9 now many libraries does not use this version, because I think good idea remove --ignore-platform-reqs

.travis.yml

@@ -32,7 +32,7 @@ install:
 before_script:
   - |
     install_package() {
-        composer require --ignore-platform-reqs $@;
+        composer require $@;
         EXIT_CODE=$?;
 
         MESSAGE="";