Use setuptools_scm for versioning

[aaron-skydio]

Instead of checking in the version. This means we can tag a new release
without needing to make a commit, just create a git tag. And then the
stuff in the next commit will auto publish when that happens also.

Topic: sf-auto-version

[aaron-skydio]

Reviews in this chain:
└#417 Use setuptools_scm for versioning
　└#418 Publish automatically to PyPI

[aaron-skydio]

#	head	base	diff	date	summary
0	7dffc872	079830ae	diff	Jan 3 11:35 AM	12 files changed, 61 insertions(+), 70 deletions(-)
1	bce9c44a	079830ae	diff	Jan 3 12:22 PM	2 files changed, 11 insertions(+), 11 deletions(-)
2	2a5d6a28	079830ae	diff	Jan 3 12:52 PM	1 file changed, 1 insertion(+), 1 deletion(-)
3	537801a5	079830ae	diff	Jan 5 21:18 PM	2 files changed, 5 insertions(+), 4 deletions(-)
4	3d957dbe	079830ae	diff	Jan 5 21:24 PM	1 file changed, 1 insertion(+), 1 deletion(-)
5	6c93c084	079830ae	diff	Jan 5 22:19 PM	3 files changed, 10 insertions(+), 3 deletions(-)
6	96c8faac	079830ae	diff	Jan 5 22:29 PM	1 file changed, 12 insertions(+)
7	838199e7	079830ae	diff	Jan 7 21:17 PM	1 file changed, 28 insertions(+), 20 deletions(-)