Use gofumpt to format code

gofumpt (mvdan.cc/gofumpt) is a fork of gofmt with stricter rules.

Brought to you by

	git ls-files \*.go | grep -v ^vendor/ | xargs gofumpt -s -w

Looking at the diff, all these changes make sense.

Also, replace gofmt with gofumpt in golangci.yml.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

checkpoint.go

@@ -85,7 +85,7 @@ func prepareImagePaths(context *cli.Context) (string, string, error) {
 		imagePath = getDefaultImagePath(context)
 	}
 
-	if err := os.MkdirAll(imagePath, 0600); err != nil {
+	if err := os.MkdirAll(imagePath, 0o600); err != nil {
 		return "", "", err
 	}
 
@@ -109,7 +109,6 @@ func prepareImagePaths(context *cli.Context) (string, string, error) {
 	}
 
 	return imagePath, parentPath, nil
-
 }
 
 func setPageServer(context *cli.Context, options *libcontainer.CriuOpts) {