Update README.md

Author: long2ice

README.md

@@ -232,3 +232,7 @@ xdg-open htmlcov/index.html
 ## License
 
 This project is licensed under the [Apache-2.0](https://github.com/long2ice/fastapi-cache/blob/master/LICENSE) License.
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+## Sponsor
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+[![Powered by DartNode](https://dartnode.com/branding/DN-Open-Source-sm.png)](https://dartnode.com "Powered by DartNode - Free VPS for Open Source")