Use `xerrors` package

[sergefdrv]

What we could also do is to use "github.com/pkg/errors" package for wrapping error messages in the context of the call stack.

Originally posted by @sergefdrv in #102

[sergefdrv]

As discussed in #148 (comment), we should use golang.org/x/xerrors package to wrap errors

xerrors.Errorf("failed to ...: %w", err)

create error values attributed with stack trace

xerrors.New("...")

and the report errors with extra details (stack trace) useful to diagnose errors

logger.Debugf("%+v", err)