downgrade go-sql-driver/mysql to v1.8.1

As of go-sql-driver/mysql v1.9.0, the "charset" parameter is not functional.
Support for this parameter is expected in a future version: go-sql-driver/mysql#1679

Author: pirosiki197

go.mod

@@ -14,7 +14,7 @@ require (
 	github.com/gliderlabs/ssh v0.3.8
 	github.com/go-git/go-git/v5 v5.14.0
 	github.com/go-playground/webhooks/v6 v6.4.0
-	github.com/go-sql-driver/mysql v1.9.0
+	github.com/go-sql-driver/mysql v1.8.1
 	github.com/golang/mock v1.6.0
 	github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510
 	github.com/google/wire v0.6.0

go.sum

@@ -293,8 +293,8 @@ github.com/go-openapi/swag v0.23.0/go.mod h1:esZ8ITTYEsH1V2trKHjAN8Ai7xHb8RV+YSZ
 github.com/go-playground/webhooks/v6 v6.4.0 h1:KLa6y7bD19N48rxJDHM0DpE3T4grV7GxMy1b/aHMWPY=
 github.com/go-playground/webhooks/v6 v6.4.0/go.mod h1:5lBxopx+cAJiBI4+kyRbuHrEi+hYRDdRHuRR4Ya5Ums=
 github.com/go-sql-driver/mysql v1.6.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=
-github.com/go-sql-driver/mysql v1.9.0 h1:Y0zIbQXhQKmQgTp44Y1dp3wTXcn804QoTptLZT1vtvo=
-github.com/go-sql-driver/mysql v1.9.0/go.mod h1:pDetrLJeA3oMujJuvXc8RJoasr589B6A9fwzD3QMrqw=
+github.com/go-sql-driver/mysql v1.8.1 h1:LedoTUt/eveggdHS9qUFC1EFSa8bU2+1pZjSRpvNJ1Y=
+github.com/go-sql-driver/mysql v1.8.1/go.mod h1:wEBSXgmK//2ZFJyE+qWnIsVGmvmEKlqwuVSjsCm7DZg=
 github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=
 github.com/go-task/slim-sprig/v3 v3.0.0 h1:sUs3vkvUymDpBKi3qH1YSqBQk9+9D/8M2mN1vB6EwHI=
 github.com/go-task/slim-sprig/v3 v3.0.0/go.mod h1:W848ghGpv3Qj3dhTPRyJypKRiqCdHZiAzKg9hl15HA8=

pkg/infrastructure/dbmanager/mariadb.go

@@ -31,6 +31,9 @@ func NewMariaDBManager(c MariaDBConfig) (domain.MariaDBManager, error) {
 	conf.Addr = fmt.Sprintf("%s:%d", c.Host, c.Port)
 	conf.User = c.AdminUser
 	conf.Passwd = c.AdminPassword
+	// TODO: As of go-sql-driver/mysql v1.9.0, the "charset" parameter is not functional.
+	// Support for this parameter is expected in a future version:
+	// https://github.com/go-sql-driver/mysql/pull/1679
 	conf.Params = map[string]string{
 		"charset": "utf8mb4",
 	}