Add license and copyright notice (#245)

rules/select_file.bzl

@@ -1,3 +1,17 @@
+# Copyright 2020 The Bazel Authors. All rights reserved.
+#
+# 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.
+
 """
 select_file() build rule implementation.
 

tests/select_file/BUILD

@@ -1,6 +1,8 @@
 load("//rules:select_file.bzl", "select_file")
 load("//rules:diff_test.bzl", "diff_test")
 
+licenses(["notice"])
+
 filegroup(
     name = "fg",
     srcs = [