Bump Guzzle dependency to v7

[incoming-th]

Hi,

Seems like this package needs to bump Guzzle to actual v7 as v6 is recommended for PHP <8

https://github.com/guzzle/guzzle

• Root composer.json requires oracle/oci-php-sdk * -> satisfiable by oracle/oci-php-sdk[0.1.0].
• oracle/oci-php-sdk 0.1.0 requires guzzlehttp/guzzle ^6.5 -> found guzzlehttp/guzzle[6.5.0, ..., 6.5.8] but it conflicts with your root composer.json require (^7.2).

Thanks