Drop support for Go 1.21 (#6046)

Co-authored-by: Chester Cheung <cheung.zhy.csu@gmail.com>

.github/workflows/ci.yml

@@ -101,7 +101,7 @@ jobs:
  compatibility-test:
  strategy:
  matrix:
- go-version: ["1.23.0", "~1.22.4", "~1.21.12"]
+ go-version: ["1.23.0", "~1.22.4"]
  platform:
  - os: ubuntu-latest
  arch: "386"

CHANGELOG.md

@@ -8,6 +8,10 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ## [Unreleased]
 
+### Removed
+
+- Drop support for [Go 1.21]. (#6046)
+
 <!-- Released section -->
 <!-- Don't change this section unless doing release -->
 

README.md

@@ -52,22 +52,16 @@ This project is tested on the following systems.
 | -------- | ---------- | ------------ |
 | Ubuntu | 1.23 | amd64 |
 | Ubuntu | 1.22 | amd64 |
-| Ubuntu | 1.21 | amd64 |
 | Ubuntu | 1.23 | 386 |
 | Ubuntu | 1.22 | 386 |
-| Ubuntu | 1.21 | 386 |
 | macOS 13 | 1.23 | amd64 |
 | macOS 13 | 1.22 | amd64 |
-| macOS 13 | 1.21 | amd64 |
 | macOS | 1.23 | arm64 |
 | macOS | 1.22 | arm64 |
-| macOS | 1.21 | arm64 |
 | Windows | 1.23 | amd64 |
 | Windows | 1.22 | amd64 |
-| Windows | 1.21 | amd64 |
 | Windows | 1.23 | 386 |
 | Windows | 1.22 | 386 |
-| Windows | 1.21 | 386 |
 
 While this project should work for other systems, no compatibility guarantees
 are made for those systems currently.