docs: Add guide on making a new SDK release

Also point the documentation to the latest release.

Change-Id: Iaa97401ea5456b55acbc9a17b551eb55a802207a
diff --git a/docs/toc.md b/docs/toc.md
index f095fe4..03c2ad7 100644
--- a/docs/toc.md
+++ b/docs/toc.md
@@ -54,6 +54,7 @@
     * [Running tests](contributing/testing.md)
     * [Common tasks](contributing/common-tasks.md)
     * [Embedding Perfetto](contributing/embedding.md)
+    * [Releasing the SDK](contributing/sdk-releasing.md)
 
 * [Design documents](#)
     * [API and ABI surface](design-docs/api-and-abi.md)