Displays a message when using with WooCommerce > 7.8.0

[sburlot]

Release note claims "[Tested Against] Woocommerce 8.0.0", but the plugins displays a message when using WooCommerce > 7.8.0
"A version of the PostFinanceCheckout plugin is yet to be released for this version of WooCommerce."

Change the line
const WC_MAXIMUM_VERSION = '7.8.0';
in woocommerce-postfinancecheckout.php
to
const WC_MAXIMUM_VERSION = '8.0.0';