docs: add licence and contribution paragraphs

Signed-off-by: Philipp Bolte <philipp.bolte@spherity.com>

README.md

@@ -78,3 +78,33 @@ voting process is needed here which should make development easier and faster. T
 used for production purposes.
 
 ![Safe screenshot with trusted issuer app](./img/safe-pbl.png)
+
+---
+
+## 🤝 Contributing
+
+OCI encourages contributions from OCI member and non-member companies and individuals.
+Please send issues and pull requests by following our processes and agreements. Feel free to check the issues page.
+
+**By contributing, companies and individuals certify the assertions made in
+the [Developer's Certificate of Origin](https://developercertificate.org/).**
+
+## 🏷️ Licence
+
+By submitting their contribution to OCI, the contributor certifies that they have the right to submit it under the open
+source license indicated here.
+
+**This project is [Apache 2.0](http://www.apache.org/licenses/LICENSE-2.0)-licensed.**
+
+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](http://www.apache.org/licenses/LICENSE-2.0)
+
+Unless required by applicable law or agreed to in writing, material
+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.
+
+Copyright © 2023 Named editors. Contributors to [OCI](https://www.oc-i.org/).