Update README.md (#8628)

Add standard section on security issues below the "file an issue via GitHub Issues' bullet.

Author: joshfree

README.md

@@ -50,6 +50,10 @@ Libraries which enable you to provision specific resources. They are responsible
 * File an issue via [Github Issues](../../issues)
 * Check [previous questions](https://stackoverflow.com/questions/tagged/azure+python) or ask new ones on StackOverflow using `azure` and `python` tags.
 
+### Reporting security issues and security bugs
+
+Security issues and bugs should be reported privately, via email, to the Microsoft Security Response Center (MSRC) <secure@microsoft.com>. You should receive a response within 24 hours. If for some reason you do not, please follow up via email to ensure we received your original message. Further information, including the MSRC PGP key, can be found in the [Security TechCenter](https://www.microsoft.com/msrc/faqs-report-an-issue).
+
 ## Contributing
 For details on contributing to this repository, see the [contributing guide](CONTRIBUTING.md).