v0.13.1

Three defects reported in #35, each with a reproduction, each real. go doc -all against 0.13.0 is unchanged in di and dihttp; an upgrade cannot
break a caller, and every fix turns a panic, a false rejection or a lost
error into the behaviour the documentation already promised.

Fixed

• Wire and Wrap accepted a result merely assignable to the key, such as a
  chan int for a <-chan int key or a []byte for a named slice type, and
  then stored it as the constructor's own type, so Get panicked asserting
  it. The value is stored as the key's type now (#35).
• Validate reported a cycle where a valid graph visited one Scoped
  binding in two scopes. A node on its path is now a binding in a holder, as
  it is on a resolution path at run time, so the two instances are told
  apart (#35).
• A Worker that returned its own failure joined with the cancellation, as
  errors.Join(ctx.Err(), err), had the failure dropped with the
  cancellation, and Stop returned nil. Only an error that says nothing
  beyond the cancellation is dropped now (#35).