BaseTools/PatchCheck: Support Contribution Agreement 1.1

https://bugzilla.tianocore.org/show_bug.cgi?id=628



Update PatchCheck.py to support either
"Contributed-under: TianoCore Contribution Agreement 1.0"
or "Contributed-under: TianoCore Contribution Agreement 1.1"
in the commit message.

Temporarily continue to allow the TianoCore Contribution
Agreement 1.0 agreement.

Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Andrew Fish <afish@apple.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>