Replace deprecated third-party dependencies

[mikeharder]

Running rush install reports 4 deprecated third-party dependencies:

../../packages/spec                      |  WARN  deprecated prex@0.4.9
../../packages/spec                      |  WARN  deprecated w3c-hr-time@1.0.2
../../packages/website                   |  WARN  deprecated trim@0.0.1
../../packages/website                   |  WARN  deprecated stable@0.1.8

[markcowl]

Closing as obsolete