Advisories for Cargo/Futures-Task package

Affected versions of the crate did not properly implement a 'static lifetime bound on the waker function. This resulted in a use-after-free if Waker::wake() is called after original data had been dropped. The flaw was corrected by adding 'static lifetime bound to the data waker takes.

Affected versions of the crate used a UnsafeCell in thread-local storage to return a noop waker reference, assuming that the reference would never be returned from another thread. This resulted in a segmentation fault crash if Waker::wake_by_ref() was called on a waker returned from another thread due to it attempting to dereference a pointer that wasn't accessible from the main thread.