API client class v1.1.72

• added property $request_timeout to control the cURL option CURLOPT_TIMEOUT, contributed by @mreho
• added setter and getter for $request_timeout, contributed by @mreho
• changed default value for the cURL option CURLOPT_HTTP_VERSION to CURL_HTTP_VERSION_1_1:
  • as of cURL version 7.62.0 the default value is CURL_HTTP_VERSION_2TLS which may cause issues
  • https://curl.se/libcurl/c/CURLOPT_HTTP_VERSION.html
• added property $curl_http_version to hold the value for CURLOPT_HTTP_VERSION
• added setter and getter for $curl_http_version
• switched to using a constant to hold the class version
• updated the README file