Update link in contributing guide
The link pointed to the website, this information is out of date, the
correct place to start discussions is the mailing list.
Signed-off-by: Janos Follath <janos.follath@arm.com>
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index c1ae452..7a0d95d 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -14,7 +14,7 @@
Making a Contribution
---------------------
-1. [Check for open issues](https://github.com/ARMmbed/mbedtls/issues) or [start a discussion](https://tls.mbed.org/discussions) around a feature idea or a bug.
+1. [Check for open issues](https://github.com/ARMmbed/mbedtls/issues) or [start a discussion](https://lists.trustedfirmware.org/mailman/listinfo/mbed-tls) around a feature idea or a bug.
1. Fork the [Mbed TLS repository on GitHub](https://github.com/ARMmbed/mbedtls) to start making your changes. As a general rule, you should use the ["development" branch](https://github.com/ARMmbed/mbedtls/tree/development) as a basis.
1. Write a test which shows that the bug was fixed or that the feature works as expected.
1. Send a pull request (PR) and work with us until it gets merged and published. Contributions may need some modifications, so a few rounds of review and fixing may be necessary. We will include your name in the ChangeLog :)