Move notebooks to next release

CHANGELOG.md

@@ -4,7 +4,7 @@ All notable changes to the "idl" extension will be documented in this file.
 
 For much more detail on incremental work for large features, see our [developer notes](./extension/docs/developer/dev-notes/README.md).
 
-## 3.1.0 Unreleased
+## 3.1.1 Unreleased
 
 Preview release of IDL Notebooks! This is a first pass at adding notebook support for IDL which is independent from Jupyter.
 
@@ -30,6 +30,8 @@ Here are some of the features that notebooks bring:
 
 - Only support for IDL code (no Python or other languages at this time)
 
+## 3.1.0 July 2023
+
 Fixed an issue where garbage collection was not turning on and caused out-of-memory errors which led to language server crashes
 
 Added a cache to reduce memory usage for worker threads (large workspaces with 300+ files should use about 50% less RAM). Coincidentally this also improved performance as well.