Gci: fix panic (#1292)

Signed-off-by: Xiang Dai <long0dai@foxmail.com>

Author: daixiang0

go.mod

@@ -6,7 +6,7 @@ require (
 	github.com/Djarvur/go-err113 v0.0.0-20200511133814-5174e21577d5
 	github.com/OpenPeeDeeP/depguard v1.0.1
 	github.com/bombsimon/wsl/v3 v3.1.0
-	github.com/daixiang0/gci v0.0.0-20200727065011-66f1df783cb2
+	github.com/daixiang0/gci v0.2.1
 	github.com/denis-tingajkin/go-header v0.3.1
 	github.com/fatih/color v1.9.0
 	github.com/go-critic/go-critic v0.5.0

go.sum

@@ -46,8 +46,8 @@ github.com/coreos/go-systemd v0.0.0-20190321100706-95778dfbb74e/go.mod h1:F5haX7
 github.com/coreos/pkg v0.0.0-20180928190104-399ea9e2e55f/go.mod h1:E3G3o1h8I7cfcXa63jLwjI0eiQQMgzzUDFVpN/nH/eA=
 github.com/cpuguy83/go-md2man/v2 v2.0.0/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
-github.com/daixiang0/gci v0.0.0-20200727065011-66f1df783cb2 h1:3Lhhps85OdA8ezsEKu+IA1hE+DBTjt/fjd7xNCrHbVA=
-github.com/daixiang0/gci v0.0.0-20200727065011-66f1df783cb2/go.mod h1:+AV8KmHTGxxwp/pY84TLQfFKp2vuKXXJVzF3kD/hfR4=
+github.com/daixiang0/gci v0.2.1 h1:NKECbLOZsPCh/38vDmWQfYK+rxoFE9EgizSb0SMIt3U=
+github.com/daixiang0/gci v0.2.1/go.mod h1:+AV8KmHTGxxwp/pY84TLQfFKp2vuKXXJVzF3kD/hfR4=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=