feat(artifact-registry): add support for code repositories with multiple apps

Closes #65

See merge request !74

Add a variable called `ARTIFACT_REGISTRY_IMAGE_NAME` to allow the names
assigned to images pushed to Artifact Registry to be overridden. This supports
the situation where multiple apps are present in the same source code
repository as the image name can be customised for each app.

docs: fix changelog entry date

See merge request !77

docs: add missing CHANGELOG entry for check_latest_tag_in_changelog fix

See merge request !76

fix: getting the latest tag in the changelog expected a space after the square...

Closes #61

See merge request !75

fix: getting the latest tag in the changelog expected a space after the square brackets containing the semver. This isn't always the case, so don't assume this

feat(pre-commit): add support for Docker

Closes #62

See merge request !71

Add a docker service to the pre-commit job and appropriate variables to
allow pre-commit jobs to use docker images should they desire.

Since this change involves adding a `before_script`, future-proof
ourselves against jobs wanting to customise the `before_script` section
of the config by making `pre-commit` into a template job. This means
that jobs can *extend* `before_script` using `!reference` tags.

Closes #62

feat(python-tox): allow specifying version of tox

Closes #63

See merge request !72

Add a variable called `TOX_REQUIREMENT` which allows downstream
consumers to override the version of tox installed and used.

Closes #63

feat(terraform-module): allow composition with Auto DevOps modules

Closes #59

See merge request !70

The stock `Terraform-Module` template from GitLab defines its own stages
which are _almost_ compatible with Auto DevOps but not quite.

Issue #59 initially proposed re-working `terraform-module.yml` to be
based on the base template but, really, the only thing that needed to be
done was to move the `fmt` job from the `validate` stage to `test`.

(Arguably `fmt` could be replaced by stuff from
`/auto-devops/terraform-pipeline.yml` but that's for another day.)

Instead of copy-pasting the module, simply import the Auto DevOps stages
and move the `fmt` job.

While we're here, and because this is supposed to be "the One Template
To Rule Them All" for terraform modules, also add in a default
`workflow` template *a la* `common-pipeline.yml`.

feat(terraform-pipeline.yml): enable git tag pipelines and targeted Terraform actions

See merge request !69

Add documentation for extending python:tox before_script

See merge request !68

fix: add missing CHANGELOG entry for release-it

See merge request !67

Add release-it template

See merge request !65

fix: remove deprecated license scanning job

Closes #56

See merge request !66

The license scanning job was deprecated in GitLab 15.9 and removed in
16.3. Explicitly disable the job since AutoDevOps brings it in
automatically.

Closes #56

Add commitlint template

Closes #55

See merge request !64

Add gitlab-ci yaml schema to settings

Closes #52

See merge request !63

doc: record the consensus decision on default workflow rules

Closes #54

See merge request !62

Closes #54

update the job rules templates to enable jobs on push and MRs

See merge request !61

Added new template which extends the GitLab Terraform Module

See merge request !59

Relates to #54.

Previously we went to some length to disable jobs using the common job
rules from running in push pipelines if there is an open MR. As noted
in #54, this is sub-optimal since the Auto DevOps container scanning
jobs, etc only run in push pipelines.

As such, let the upstream user of the jobs decide on their own workflow
rules policy because they are the best placed to decide if they care
about Auto DevOps jobs.

Ensure tag matches the latest tag defined in the CHANGELOG. Split out CHANGELOG checking to a separate template to allow for reuse.