Upgrade gopkg.in/yaml to v3

Fixes vulnerability: https://github.com/advisories/GHSA-hp87-p4gw-j4gq

YAML v3 deserializes maps as map[string]interface{} so we handle this in
MapImportSource now.

Signed-off-by: Jesse Szwedko <jesse@szwedko.me>

internal/genflags/cmd/genflags/main.go

@@ -15,7 +15,7 @@ import (
 
 	"github.com/urfave/cli/v2"
 	"github.com/urfave/cli/v2/internal/genflags"
-	"gopkg.in/yaml.v2"
+	"gopkg.in/yaml.v3"
 )
 
 const (