ubuntu-latest is in the process of being updated from ubuntu-22.04 to
ubuntu-24.04, which leads to issues with py37:

```
Version 3.7 was not found in the local cache
Error: The version '3.7' with architecture 'x64' was not found for Ubuntu 24.04.
```

This commit hard-codes the ubuntu-version for py37 to ubuntu-22.04,
similar to what we've done for py36.

See https://github.com/actions/runner-images/issues/10636 for more
information.

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 5.1.1 to 5.2.0.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](https://github.com/actions/setup-python/compare/v5.1.1...v5.2.0

)

---
updated-dependencies:
- dependency-name: actions/setup-python
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

3.12 is current now.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 5.1.0 to 5.1.1.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](https://github.com/actions/setup-python/compare/v5.1.0...v5.1.1

)

---
updated-dependencies:
- dependency-name: actions/setup-python
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 5.0.0 to 5.1.0.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](https://github.com/actions/setup-python/compare/v5.0.0...v5.1.0

)

---
updated-dependencies:
- dependency-name: actions/setup-python
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

This was lost when Travis stopped working, so our coveralls data
is frozen in 2021. This should get it working again using
https://github.com/marketplace/actions/coveralls-github-action


and allow coveralls to post comments on PRs.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

I think we can just do this now Python 3.12 is stable.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 4.8.0 to 5.0.0.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](https://github.com/actions/setup-python/compare/v4.8.0...v5.0.0

)

---
updated-dependencies:
- dependency-name: actions/setup-python
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 4.7.1 to 4.8.0.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](https://github.com/actions/setup-python/compare/v4.7.1...v4.8.0

)

---
updated-dependencies:
- dependency-name: actions/setup-python
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 4.7.0 to 4.7.1.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](https://github.com/actions/setup-python/compare/v4.7.0...v4.7.1

)

---
updated-dependencies:
- dependency-name: actions/setup-python
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v3...v4

)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 4.6.1 to 4.7.0.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](https://github.com/actions/setup-python/compare/v4.6.1...v4.7.0

)

---
updated-dependencies:
- dependency-name: actions/setup-python
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 4.6.0 to 4.6.1.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](https://github.com/actions/setup-python/compare/v4.6.0...v4.6.1

)

---
updated-dependencies:
- dependency-name: actions/setup-python
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 4.5.0 to 4.6.0.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](https://github.com/actions/setup-python/compare/v4.5.0...v4.6.0

)

---
updated-dependencies:
- dependency-name: actions/setup-python
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

This drops the travis-ci config and adds config for running tests
via tox in Github Actions. It also updates the list of envs in
tox.ini for recent Python 3 versions.

Signed-off-by: Adam Williamson <awilliam@redhat.com>