install failed via `go get`

[yunfan]

os: ubuntu 21.04
arch: x86_64
goversion: go version go1.16.2 linux/amd64

log:

oem@pc:~$ go get github.com/gushitong/rekkles                                                                                          
go: downloading github.com/gushitong/rekkles v0.0.0-20181102035910-f22ec09f5f24                                                        
go: downloading github.com/dgraph-io/badger v1.6.2                                                                                     
go: downloading github.com/pkg/errors v0.9.1                                                                                           
go: downloading github.com/tidwall/redcon v1.4.1                                                                                       
go: downloading github.com/tidwall/btree v0.4.2                                                                                        
go: downloading github.com/tidwall/match v1.0.3                                                                                        
go: downloading github.com/dgraph-io/ristretto v0.0.2                                                                                  
go: downloading github.com/dustin/go-humanize v1.0.0                                                                                   
go: downloading github.com/golang/protobuf v1.3.1                                                                                      
go: downloading golang.org/x/net v0.0.0-20190620200207-3b0461eec859                                                                    
go: downloading golang.org/x/sys v0.0.0-20190626221950-04f50cda93cb                                                                    
go: downloading github.com/AndreasBriese/bbloom v0.0.0-20190825152654-46b345b51c96                                                     
go: downloading github.com/cespare/xxhash v1.1.0                                                                                       
# github.com/gushitong/rekkles/engine                                                                                                  
go/pkg/mod/github.com/gushitong/rekkles@v0.0.0-20181102035910-f22ec09f5f24/engine/badger.go:113:14: t.Txn.SetWithTTL undefined (type *b
adger.Txn has no field or method SetWithTTL)                                                                                           
go/pkg/mod/github.com/gushitong/rekkles@v0.0.0-20181102035910-f22ec09f5f24/engine/badger.go:140:6: opts.Dir undefined (type func(string
) badger.Options has no field or method Dir)                                                                                           
go/pkg/mod/github.com/gushitong/rekkles@v0.0.0-20181102035910-f22ec09f5f24/engine/badger.go:141:6: opts.ValueDir undefined (type func(s
tring) badger.Options has no field or method ValueDir)                                                                                 
go/pkg/mod/github.com/gushitong/rekkles@v0.0.0-20181102035910-f22ec09f5f24/engine/badger.go:142:6: opts.SyncWrites undefined (type func
(string) badger.Options has no field or method SyncWrites)                                                                             
go/pkg/mod/github.com/gushitong/rekkles@v0.0.0-20181102035910-f22ec09f5f24/engine/badger.go:143:25: cannot use opts (type func(string) 
badger.Options) as type badger.Options in argument to badger.Open                                                                      
go/pkg/mod/github.com/gushitong/rekkles@v0.0.0-20181102035910-f22ec09f5f24/engine/badger.go:147:24: cannot use opts (type func(string) 
badger.Options) as type badger.Options in field value