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>

libcontainer/cgroups/fs2/defaultpath.go

@@ -82,9 +82,7 @@ func parseCgroupFile(path string) (string, error) {
 }
 
 func parseCgroupFromReader(r io.Reader) (string, error) {
-	var (
-		s = bufio.NewScanner(r)
-	)
+	s := bufio.NewScanner(r)
 	for s.Scan() {
 		var (
 			text  = s.Text()