update release docs for 4.0

[ctb]

4.0.0.rc1 release process is revealing problems with https://sourmash.readthedocs.io/en/latest/release.html --

• need to install tox, and maybe tox-conda
• and/or default to python=3.8 for sourmash-rc

currently trying:

conda create -y -n sourmash-rc2 python=3.8 pip cxx-compiler make tox tox-conda twine

[ctb]

I'm at the testenv2 part of the release notes.

# Secondly we test via pip

cd ../../testenv2
deactivate
source bin/activate
python -m pip install -U setuptools pip wheel
python -m pip install -e git+https://github.com/dib-lab/sourmash.git@v${new_version}${rc}#egg=sourmash[test]
cd src/sourmash
make test
make dist
cp dist/sourmash*tar.gz ../../../testenv3/

but the make dist is producing sourmash-0.0.0.tar.gz instead of sourmash-4.0.0rc1.tar.gz.

the correct tag is checked out -

$ git describe --tag
v4.0.0rc1

src/version.py is correct:

$ more src/sourmash/version.py
# coding: utf-8
# file generated by setuptools_scm
# don't change, don't track in version control
version = '4.0.0rc1'
version_tuple = (4, 0, '0rc1')

...ok.

turns out setuptools_scm wasn't installed. Once I did pip install setuptools_scm it all worked fine.

I don't really understand the installation message --

$ pip install setuptools_scm
Collecting setuptools_scm
  Using cached setuptools_scm-5.0.1-py2.py3-none-any.whl (28 kB)
Requirement already satisfied: setuptools in /tmp/tmp.wjPtg5lPIm/testenv2/lib/python3.8/site-packages (from setuptools_scm) (53.0.0)
Installing collected packages: setuptools-scm
Successfully installed setuptools-scm-5.0.1

- like, if it was already satisfied, why is it installing it??

I also don't understand why it wasn't installed by the pip install command used to install sourmash from git+https...

[ctb]

happened again for the next section on testenv3 - make dist didn't find the right version #, since setuptools_scm wasn't installed.

[ctb]

also looks like the docs are not picking up the "4.0" version.

[ctb]

also looks like the docs are not picking up the "4.0" version.

ok, that was just because it built off of 'latest' immediately after #1283 was merged, and before the tag was there. I forced a rebuild and it's happy now!