Remove detailed test matrix information from README. Moved to eswiki.
Remove detailed test matrix information from README. Moved to eswiki.

unikent/splunk-sdk-php,unikent/splunk-sdk-php,shakeelmohamed/splunk-sdk-php,unikent/splunk-sdk-php,splunk/splunk-sdk-php,shakeelmohamed/splunk-sdk-php,splunk/splunk-sdk-php,shakeelmohamed/splunk-sdk-php,splunk/splunk-sdk-php