Fix deprecation

[John Mortlock (jmortlock)]

WHY

Resolves the following warning when used with Symfony 7:

[2024-11-03T04:46:18.378993+00:00] deprecation.INFO: User Deprecated: Method 
"Symfony\Component\HttpKernel\Bundle\Bundle::build()" might add "void" as a native return type declaration in the future. 
Do the same in child class "Contentful\ContentfulBundle\ContentfulBundle" now to avoid 
errors or add an explicit @return annotation to suppress this message. {"exception":"[object] (ErrorException(code: 0): 
User Deprecated: Method \"Symfony\\Component\\HttpKernel\\Bundle\\Bundle::build()\" 
might add \"void\" as a native return type declaration in the future. Do the same in 
child class \"Contentful\\ContentfulBundle\\ContentfulBundle\" now to avoid 
errors or add an explicit @return annotation to suppress this message. 
at /var/www/html/member-portal/vendor/symfony/error-handler/DebugClassLoader.php:341)"}