I posted about a preliminary version a few months ago. The package is now registered.
From the README:
For some applications, LinearAlgebra wants to know if a matrix is exactly Hermitian. Quantum information packages, on the other hand, might want to know if a matrix is approximately (or exactly) Hermitian. Furthermore, many functions that check whether a property (approximately) holds are interdependent. For example isdiag calls functions that eventually call iszero. And isposdef calls ishermitian. Furthermore again, one might want to check approximate equality in norm; or elementwise. One might want to specify a tolerance and have it propagate. In practice, packages tend to reimplement tests in ways that do not satisfy all these criteria, and fail to be composable…Clearly, a general interface for approximate equality is needed.