Release process for `pygraphviz`

Introduction

Example version number

1.8.dev0 # development version of 1.8 (release candidate 1)
1.8rc1 # 1.8 release candidate 1
1.8rc2.dev0 # development version of 1.8 release candidate 2
1.8 # 1.8 release
1.9.dev0 # development version of 1.9 (release candidate 1)

Process

Set release variables:
```
export VERSION=<version number>
export PREVIOUS=<previous version number>
export ORG="pygraphviz"
export REPO="pygraphviz"
```
If this is a prerelease:

export NOTES="doc/source/release/release_dev.rst"

If this is release:

export NOTES="doc/source/release/release_${VERSION}.rst" git rm doc/source/release/release_dev.rst

Autogenerate release notes:

changelist ${ORG}/${REPO}  pygraphviz-${PREVIOUS} main --version ${VERSION}  --out ${NOTES} --format rst

Edit doc/source/_static/version_switcher.json in order to add the release, move the key value pair "preferred": true to the most recent stable version, and commit.
Update version in pygraphviz/__init__.py.

Commit changes:

git add pygraphviz/__init__.py ${NOTES} doc/source/_static/version_switcher.json
git commit -m "Designate ${VERSION} release"

Tag the release in git:
```
git tag -s pygraphviz-${VERSION} -m "signed ${VERSION} tag"
```
If you do not have a gpg key, use -u instead; it is important for Debian packaging that the tags are annotated
Push the new meta-data to github:
```
git push --tags origin main
```
where origin is the name of the github.com:pygraphviz/pygraphviz repository

Review the github release page:

https://github.com/pygraphviz/pygraphviz/tags

Update documentation on the web: The documentation is kept in a separate repo: pygraphviz/documentation
- Wait for the CI service to deploy to GitHub Pages
- Sync your branch with the remote repo: git pull.
- Copy the documentation built by the CI service. Assuming you are at the top-level of the documentation repo:
```
# FIXME - use eol_banner.html
cp -a latest ../pygraphviz-${VERSION}
git reset --hard <commit from last release>
mv ../pygraphviz-${VERSION} .
rm -rf stable
cp -rf pygraphviz-${VERSION} stable
git add pygraphviz-${VERSION} stable
git commit -m "Add ${VERSION} docs"
git push  # force push---be careful!
```
Update version in pygraphviz/__init__.py.

Commit changes:

git add pygraphviz/__init__.py
git commit -m 'Bump version'
git push origin main