Write a basic README.md

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README.md

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 # aas-core3.0-java
-Manipulate, verify and de/serialize asset administration shells in Java.
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+[![CI](https://github.com/aas-core-works/aas-core3.0-java/actions/workflows/ci.yml/badge.svg)](https://github.com/aas-core-works/aas-core3.0-java/actions/workflows/ci.yml)
+[![Build Documentation](https://github.com/aas-core-works/aas-core3.0-java/actions/workflows/build-doc.yaml/badge.svg)](https://github.com/aas-core-works/aas-core3.0-java/actions/workflows/build-doc.yaml)
+
+This is a software development kit (SDK) to manipulate, verify and de/serialize Asset Administration Shells based on the version 3.0 of the meta-model.
+
+The documentation is available on https://aas-core-works.github.io/aas-core3.0-java/.
+
+The code has been automatically generated by aas-core-codegen.
+
+If you want to contribute, please [create a new issue](https://github.com/aas-core-works/aas-core3.0-java/issues/new) first, so that we discuss and synchronize the development.