grafana-cli: Upgrade to urfave/cli v2 (#22402)

* grafana-cli: Upgrade to urfave/cli v2

pkg/cmd/grafana-cli/commands/commandstest/context.go

@@ -0,0 +1,25 @@
+package commandstest
+
+import (
+	"flag"
+	"github.com/grafana/grafana/pkg/cmd/grafana-cli/utils"
+	"github.com/urfave/cli/v2"
+)
+
+// NewCliContext creates a new CLI context with a certain set of flags.
+func NewCliContext(flags map[string]string) (*utils.ContextCommandLine, error) {
+	app := cli.App{
+		Name: "Test",
+	}
+	flagSet := flag.NewFlagSet("Test", 0)
+	for flag, value := range flags {
+		flagSet.String(flag, "", "")
+		if err := flagSet.Set(flag, value); err != nil {
+			return nil, err
+		}
+	}
+
+	return &utils.ContextCommandLine{
+		Context: cli.NewContext(&app, flagSet, nil),
+	}, nil
+}