This fixes:
pkg/services/sqlstore/migrator/migrations.go:116:18: the argument is already a string, there's no need to use fmt.Sprintf (S1025)
pkg/services/sqlstore/migrator/types.go:49:16: the argument is already a string, there's no need to use fmt.Sprintf (S1025)
* use utf8mb4 character set for connections to mysql
* use utf8mb4 character set for tables, shorten varchar fields used in unique indexes
* migration type to update table character set
* update table character sets
* set charset for temp_user.status
* gofmt