Add Alibaba Cloud ECI SDK

Alibaba Cloud ECI(Elastic Container Instance) is a service that allow you
run containers without having to manage servers or clusters.

This commit add ECI sdk for virtual kubelet.

Signed-off-by: xianwei.zw <xianwei.zw@alibaba-inc.com>
Signed-off-by: shidao.ytt <shidao.ytt@alibaba-inc.com>

vendor/github.com/aliyun/alibaba-cloud-sdk-go/sdk/auth/credential.go

@@ -0,0 +1,18 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package auth
+
+type Credential interface {
+}