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.

sysdig-sdk-python/sdcclient/_secure.py

Lines 44 to 58 in 3dd352e

	def get_rules_group(self, name):
	'''**Description**
	Retrieve a group of all rules having the given name. This is used to
	show how a base rule is modified by later rules that override/append
	to the rule.
	**Arguments**
	- name: the name of the rule group
	**Success Return Value**
	A JSON object representing the list of rules.
	'''
	res = self.http.get(self.url + '/api/secure/rules/groups?name={}'.format(name), headers=self.hdrs,
	verify=self.ssl_verify)
	return self._request_result(res)

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