replace DataDog with klauspost for zstd

go.mod

@@ -1,17 +1,17 @@
 module github.com/pingcap/tiproxy
 
-go 1.21
+go 1.19
 
 require (
 	github.com/BurntSushi/toml v1.2.1
-	github.com/DataDog/zstd v1.5.5
 	github.com/bahlo/generic-list-go v0.2.0
 	github.com/cenkalti/backoff/v4 v4.2.1
 	github.com/fsnotify/fsnotify v1.6.0
 	github.com/gin-contrib/pprof v1.4.0
 	github.com/gin-gonic/gin v1.8.1
 	github.com/go-mysql-org/go-mysql v1.6.0
 	github.com/go-sql-driver/mysql v1.7.0
+	github.com/klauspost/compress v1.16.6
 	github.com/pingcap/tidb v1.1.0-beta.0.20230103132820-3ccff46aa3bc
 	github.com/pingcap/tidb/parser v0.0.0-20230103132820-3ccff46aa3bc
 	github.com/pingcap/tiproxy/lib v0.0.0-00010101000000-000000000000