Maintainers.txt: Remove DuetPkg
Maintainers.txt: Remove DuetPkg

Since DuetPkg is due to be removed, Maintainers.txt
should also be updated.
https://bugzilla.tianocore.org/show_bug.cgi?id=1322

Cc: Hao Wu <f387b71200577e27ccf5abb090fda0ddd187ec6e@intel.com>
Cc: Andrew Fish <be8d29debaaf5173b4b7ecb4ace852732e71f7b9@apple.com>
Cc: Laszlo Ersek <7437296077edea1cb64451c122c4dac071f0cfbc@redhat.com>
Cc: Leif Lindholm <a613079f0455438b29e28a9c5b9eb3779a81a33a@linaro.org>
Cc: Michael D Kinney <fd20bc543a9f65bb633fac7d08a403c1f1c8eb6c@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Shenglei Zhang <bc08ecbbf1316cc766ca5aae38ff0e194af9f1cf@intel.com>
Reviewed-by: Ruiyu Ni <9fa3a6894a36bca79e6a72ad65af5a5702efecd1@intel.com>

MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2