🤖 Update license headers / Format go codes and yaml files

Signed-off-by: vdaas-ci <ci@vdaas.org>

.github/conflint.yaml

@@ -1,5 +1,5 @@
 kubeval:
   - files:
-    - k8s/**/*.yaml
+      - k8s/**/*.yaml
     strict: true
     ignoreMissingSchemas: true

internal/db/nosql/cassandra/cassandra_mock.go

@@ -1,3 +1,18 @@
+//
+// Copyright (C) 2019-2020 Vdaas.org Vald team ( kpango, rinx, kmrmt )
+//
+// 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
+//
+//    https://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 cassandra
 
 import "github.com/gocql/gocql"