Bump version for development of 6.0.3
Small tweak to changelog
Merge pull request #2270 from dstufft/speed-up-version-check

Speed up version check
(cherry picked from commit 34f5befaae38fe180cd1d6309558da192967f452)
Merge branch 'release/6.0.3'
bump version for release
Generate a new get-pip.py