Update gopkg.in/yaml.v2 to gopkg.in/yaml.v3 (#1766)

API v3 was released in 2019 [1]. Update from the v2 API, no changes to
the packages's use needed and no breaking changes expected.

[1] https://ubuntu.com/blog/api-v3-of-the-yaml-package-for-go-is-available

doc/yaml_docs.go

@@ -23,7 +23,7 @@ import (
 
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
-	"gopkg.in/yaml.v2"
+	"gopkg.in/yaml.v3"
 )
 
 type cmdOption struct {

go.mod

@@ -6,5 +6,5 @@ require (
 	github.com/cpuguy83/go-md2man/v2 v2.0.2
 	github.com/inconshreveable/mousetrap v1.0.1
 	github.com/spf13/pflag v1.0.5
-	gopkg.in/yaml.v2 v2.4.0
+	gopkg.in/yaml.v3 v3.0.1
 )

go.sum

@@ -8,5 +8,5 @@ github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
 github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
-gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=