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/stacktrace/capture.go

@@ -13,8 +13,8 @@ func Capture(userSkip int) Stacktrace {
 	)
 	for i := skip; ; i++ {
 		pc, file, line, ok := runtime.Caller(i)
-		//detect if caller is repeated to avoid loop, gccgo
-		//currently runs  into a loop without this check
+		// detect if caller is repeated to avoid loop, gccgo
+		// currently runs  into a loop without this check
 		if !ok || pc == prevPc {
 			break
 		}