Upates pipeline field as specified
		Args:
			pipeline_key		key for pipeline where the fields lives
			field 				StreakField object with fresh data
			returns				(status code, updated field dict)

def update_pipeline_field(self, pipeline_key, field):
		'''Upates pipeline field as specified
		Args:
			pipeline_key		key for pipeline where the fields lives
			field 				StreakField object with fresh data
			returns				(status code, updated field dict)
		'''
		uri = '/'.join([
						self.api_uri,
						self.pipelines_suffix,
						pipeline_key,
						self.fields_suffix
						])
		return self._update_field(uri, field)