Update README.md

Added a link to the contribution section pointing to the "hot to contribute" doc on the wiki.

README.md

@@ -21,3 +21,5 @@ provided by the bot. You will only need to do this once across all repos using o
 This project has adopted the [Microsoft Open Source Code of Conduct](https://opensource.microsoft.com/codeofconduct/).
 For more information see the [Code of Conduct FAQ](https://opensource.microsoft.com/codeofconduct/faq/) or
 contact [opencode@microsoft.com](mailto:opencode@microsoft.com) with any additional questions or comments.
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+For information on how to contribute, refer to the ["how to contribute"](https://github.com/Azure/Azure-Sentinel/wiki/Contribute-to-Sentinel-GitHub-Community-of-Queries) guide on the project's [wiki](https://github.com/Azure/Azure-Sentinel/wiki).