Add optional `type` parameter to get_rule_group

[iret-m-murakami]

Currently, the get_rule_group function in the sdcclient._secure.py module only allows name as input. This can lead to a Please specify rule type for rule with multiple sources error when there are multiple rule groups with the same name but different ruleType values. https://github.com/sysdiglabs/sysdig-sdk-python/blob/3dd352e89ef24aad341feff8dbb0e661b8ba795f/sdcclient/_secure.py#L44-L58

To address this, I propose adding an optional type parameter to the get_rule_group function.