Some minor changes

[grummbeer]

• using str_contains for simple text matching
• using "null safe operator" for accessing nullable objects
• sanitize trailing slash for PinFile path
• add test for xml renderer getBalances
• add a missing "declare(strict_types=1)"
• remove unused contant
• make use of given constant
• using arrow function for simple return

[grummbeer]

Are you fine with do not use getters when accessing own properties?

like this?

public function toArray(): array
{
    return [
        'bankCode' => $this->bankCode->getString(),
        'accountNumber' => $this->accountNumber,
        'accountHolderName' => $this->accountHolderName,
    ];
}

[amenk]

Are you fine with do not use getters when accessing own properties?

like this?

public function toArray(): array
{
    return [
        'bankCode' => $this->bankCode->getString(),
        'accountNumber' => $this->accountNumber,
        'accountHolderName' => $this->accountHolderName,
    ];
}

yes