chore: Enable Size-Label bot in all googleapis Java repositories (#1381)

* chore: Enable Size-Label bot in all googleapis Java repositories

Auto-label T-shirt size indicator should be assigned on every new pull request in all googleapis Java repositories

* Remove product 

Remove product since it is by default true

* add license header

Co-authored-by: Neenu Shaji <Neenu1995@users.noreply.github.com>

synthtool/gcp/templates/java_library/.github/auto-label.yaml

@@ -0,0 +1,15 @@
+# Copyright 2021 Google LLC
+#
+# 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.
+requestsize:
+  enabled: true