extension/CHANGELOG.md: prepare for v0.42.1

For #3520

Change-Id: Id21e2c86732eee2982e360e3f0356cb0f4a19a3b
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/611835
kokoro-CI: kokoro <[email protected]>
Commit-Queue: Hyang-Ah Hana Kim <[email protected]>
Reviewed-by: Robert Findley <[email protected]>

extension/CHANGELOG.md

@@ -1,10 +1,20 @@
+## v0.42.1 - 9 Sep, 2024
+
+A comprehensive list of changes can be found in the complete [commit history](https://github.com/golang/vscode-go/compare/v0.42.0..v0.42.1).
+
+### Changes
+
+* Prompt users for the [2024 Go Developer survey](https://google.qualtrics.com/jfe/form/SV_ei0CDV2K9qQIsp8?s=p). ([Issue 3517](https://github.com/golang/vscode-go/issues/3517))
+* Updated the default versions of `gomodifytags`, `impl`, `gofumpt`, and `revive`. ([CL 607757](https://go.dev/cl/607757)).
+* Increased the Go telemetry prompt rate to 25%. The new Go blog post ["Telemetry in Go 1.23 and beyond"](https://go.dev/blog/gotelemetry) discusses how Go telemetry helps improving the reliability and the performance of go toolchain programs.
+
 ## v0.43.0 - 22 Aug, 2024 (pre-release)
 
 This is the [pre-release version](https://code.visualstudio.com/api/working-with-extensions/publishing-extension#prerelease-extensions) of v0.44. The nightly (golang.go-nightly) extension will be deprecated in favor of the pre-release version.
 
 ## v0.42.0 - 17 Jul, 2024
 
-A comprehensive list of changes can be found in the complete [commit history](https://github.com/golang/vscode-go/compare/v0.42.0...v0.41.4).
+A comprehensive list of changes can be found in the complete [commit history](https://github.com/golang/vscode-go/compare/v0.41.4..v0.42.0).
 
 ### Updates in `gopls`