[release] CHANGELOG.md: v0.21.1 changelog

Change-Id: Ifd6a5200aff8bc15609924f8a35d5fe8c099c9fa
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/285257
Trust: Hyang-Ah Hana Kim <hyangah@gmail.com>
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
(cherry picked from commit 0a4362f7ed996eb9aedab495accc8b176a3c9b42)
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/285259
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 18cd091..528f564 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,11 +1,18 @@
-## v0.21.0 - 20th Jan, 2021
 > 📣 &nbsp;&nbsp;Announcement:
 > * The language server, `gopls`, will be enabled by default in the next release. ([Issue 1037](https://github.com/golang/vscode-go/issues/1037)). Please test and provide us your feedback on the `#vscode-dev` [Gophers Slack](https://gophers.slack.com/) channel.
 > * Some workspace or folder-level settings that affect tools location will not be used by default until users explicitly opt in by running `Go: Toggle Workspace Trust Flag`. See [Issue 1094](https://github.com/golang/vscode-go/issues/1094) for more information.
+## v0.21.1 - 21st Jan, 2021
+A list of all issues and changes can be found in the [v0.21.1 milestone](https://github.com/golang/vscode-go/milestone/22?closed=1).
+### Fixes
+- Fixed the `Cannot get property 'get' of undefined` error. ([Issue 1104](https://github.com/golang/vscode-go/issues/1104))
+- Restored the `"go.languageServerExperimentalFeatures"` setting for users who depend on this to run custom vet analyzers. ([Issue 1110](https://github.com/golang/vscode-go/issues/1110))
+## v0.21.0 - 20th Jan, 2021
 A list of all issues and changes can be found in the [v0.21.0 milestone](https://github.com/golang/vscode-go/milestone/16?closed=1).
 ### Enhancements
 - The new `dlvFlags` debug attribute is available for conveniently supply extra flags to `dlv`. ([Issue 978](https://github.com/golang/vscode-go/issues/978))