Dockerfile: add -y flag to apt-get, so that it can run noninteractivly

Dockerfile

@@ -1,45 +1,47 @@
-#
-# Copyright (c) nexB Inc. and others. All rights reserved.
-# SPDX-License-Identifier: Apache-2.0 AND CC-BY-4.0
-#
-# Visit https://aboutcode.org and https://github.com/nexB/scancode-toolkit for
-# support and download. ScanCode is a trademark of nexB Inc.
-#
-# The ScanCode software is licensed under the Apache License version 2.0.
-# The ScanCode open data is licensed under CC-BY-4.0.
-#
-# 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.
-#
-
-FROM python:3.6 
-
-# Requirements as per https://scancode-toolkit.readthedocs.io/en/latest/getting-started/install.html
-RUN apt-get update && apt-get install bzip2 xz-utils zlib1g libxml2-dev libxslt1-dev
-
-# Create directory for scancode sources
-RUN mkdir scancode-toolkit
-
-# Copy sources into docker container
-COPY . scancode-toolkit
-
-# Set workdir
-WORKDIR scancode-toolkit
-
-# Run scancode once for initial configuration, with --reindex-licenses to create the base license index
-RUN ./scancode --reindex-licenses
-
-# Add scancode to path
-ENV PATH=$HOME/scancode-toolkit:$PATH
-
-# Set entrypoint to be the scancode command, allows to run the generated docker image directly with the scancode arguments: `docker run (...) <containername> <scancode arguments>`
-ENTRYPOINT ["./scancode"]
+#
+# Copyright (c) nexB Inc. and others. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0 AND CC-BY-4.0
+#
+# Visit https://aboutcode.org and https://github.com/nexB/scancode-toolkit for
+# support and download. ScanCode is a trademark of nexB Inc.
+#
+# The ScanCode software is licensed under the Apache License version 2.0.
+# The ScanCode open data is licensed under CC-BY-4.0.
+#
+# 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.
+#
+
+FROM python:3.6 
+
+# Requirements as per https://scancode-toolkit.readthedocs.io/en/latest/getting-started/install.html
+RUN apt-get update \
+ && apt-get install -y bzip2 xz-utils zlib1g libxml2-dev libxslt1-dev \
+ && rm -rf /var/lib/apt/lists/*
+
+# Create directory for scancode sources
+RUN mkdir scancode-toolkit
+
+# Copy sources into docker container
+COPY . scancode-toolkit
+
+# Set workdir
+WORKDIR scancode-toolkit
+
+# Run scancode once for initial configuration, with --reindex-licenses to create the base license index
+RUN ./scancode --reindex-licenses
+
+# Add scancode to path
+ENV PATH=$HOME/scancode-toolkit:$PATH
+
+# Set entrypoint to be the scancode command, allows to run the generated docker image directly with the scancode arguments: `docker run (...) <containername> <scancode arguments>`
+ENTRYPOINT ["./scancode"]