Add .asf.yaml to apache/spark-docker

# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements. See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You 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.

# https://cwiki.apache.org/confluence/display/INFRA/git+-+.asf.yaml+features
---
github: 
  description: "Official Dockerfile for Apache Spark"
  homepage: https://spark.apache.org/
  labels: 
    - python
    - scala
    - r
    - java
    - big-data
    - jdbc
    - sql
    - spark
  enabled_merge_buttons: 
    merge: false
    squash: true
    rebase: true

notifications: 
  pullrequests: reviews@spark.apache.org
  issues: reviews@spark.apache.org
  commits: commits@spark.apache.org