PSWS-Version response header case sensitivity

[rsobap]

It seems that some web servers return this header in lowercase. This causes the version compatibility check to be ignored because the library expects the header to be exactly 'PSWS-Version': https://github.com/PrestaShop/PrestaShop-webservice-lib/blob/94feb5f547b4a33cd9c759edfa581f30fa42803b/PSWebServiceLibrary.php#L214

Example response:

HTTP/1.1 200 OK
Connection: Keep-Alive
Keep-Alive: timeout=5, max=100
access-time: 1701712674
x-powered-by: PrestaShop Webservice
psws-version: 8.1.2
content-type: text/xml;charset=utf-8
execution-time: 0.005
...
server: LiteSpeed
vary: User-Agent