Convert markdown notice to rst

Author: philpep

README.rst

@@ -1,14 +1,19 @@
-> [!IMPORTANT]
-> **Maintenance Notice**
->
-> This project is currently **not actively maintained**, and responses to issues or pull requests may be delayed for **several months**. Please consider this when using the project and feel free to contribute via pull requests, which will be reviewed as time permits. Thank you for your understanding!
-
 ##################################
 Testinfra test your infrastructure
 ##################################
 
 Latest documentation: https://testinfra.readthedocs.io/en/latest
 
+.. important::
+
+   **Maintenance Notice**
+
+   This project is currently **not actively maintained**, and responses
+   to issues or pull requests may be delayed for **several months**.
+   Please consider this when using the project and feel free to
+   contribute via pull requests, which will be reviewed as time permits.
+   Thank you for your understanding!
+
 About
 =====