Revert "Cap Pip<8 due to pip bug"

This reverts commit 308484592dd8bb993dc24a6d6aacefc611cd7e8b.
This issue has been fixed after pip 8.0.1 released.

TrivialFix

Change-Id: I193ef41c2a9efcab3aea54f4949cf6fb1e9b1084
1 file changed