docs: update README.md [skip ci]

Author: allcontributors[bot]

README.md

@@ -209,6 +209,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="https://github.com/bjarkimg"><img src="https://avatars2.githubusercontent.com/u/1289419?v=4" width="100px;" alt=""/><br /><sub><b>bjarkimg</b></sub></a><br /><a href="#question-bjarkimg" title="Answering Questions">💬</a></td>
     <td align="center"><a href="https://github.com/Bost"><img src="https://avatars0.githubusercontent.com/u/1174677?v=4" width="100px;" alt=""/><br /><sub><b>Bost</b></sub></a><br /><a href="https://github.com/ExpDev07/coronavirus-tracker-api/commits?author=Bost" title="Documentation">📖</a></td>
     <td align="center"><a href="https://github.com/gribok"><img src="https://avatars1.githubusercontent.com/u/40306040?v=4" width="100px;" alt=""/><br /><sub><b>GRIBOK</b></sub></a><br /><a href="https://github.com/ExpDev07/coronavirus-tracker-api/commits?author=gribok" title="Code">💻</a> <a href="https://github.com/ExpDev07/coronavirus-tracker-api/commits?author=gribok" title="Tests">⚠️</a></td>
+    <td align="center"><a href="https://github.com/oliver-xapix-io"><img src="https://avatars0.githubusercontent.com/u/13470858?v=4" width="100px;" alt=""/><br /><sub><b>Oliver Thamm</b></sub></a><br /><a href="https://github.com/ExpDev07/coronavirus-tracker-api/commits?author=oliver-xapix-io" title="Documentation">📖</a></td>
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 </table>