Our logic for converting npm style versions to PEP-440 style versions
was not correct in some cases. This change fixes this.
As part of this change we no longer produce a NPM version that would
be just X.Y.Z-dev, instead for development versions we always include
both the timestamp of the commit and the commit hash.
Instead of trying to use a bunch of sed logic to do our conversions,
we now have a small go program that uses a newly added library in
pkg/util. A side effect of this is that we can more easily write tests
to ensure the conversion works as expected.
Fixes#1243
7b27f00602