Sed is needed by webassembly build. Cannot use sed from msys as
having msys bin folder in path breaks webassembly build.
Task-number: QTQAINFRA-2835
Change-Id: I6ad06f0a952a0d8bc5d21e62f8c2cef70f40c618
Reviewed-by: Heikki Halmet <heikki.halmet@qt.io>
