add license header to Containerfile

Signed-off-by: Janine Olear <[email protected]>

Containerfile

@@ -1,3 +1,21 @@
+# Copyright 2024 The Sigstore Authors
+#
+# 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.
+
+"""For the stable high-level API, see model_signing.api."""
+
+__version__ = "0.1.1"
+
 FROM python:3.13-slim
 
 COPY pyproject.toml ./