feat: add mkdocs template

See merge request !91

Add a new template to the common pipleine which builds documentation if
a mkdocs.yml file is present in the root of the repository. Nothing is
done if no file is present and all jobs can be disabled via variables
which makes these jobs "safe" to add to the common pipeline.

feat: add terraform-fmt job

See merge request !90

fix: remove fmt job reference from terraform-module.yml

See merge request !89

feat(terraform): expose local files directory

Closes #72

See merge request !88

Expose the concept of a "local files" directory to terraform
configurations. Configurations can load this via a variable named
"local_files_dir".

Such a directory will be copied from plan jobs to apply jobs and is
useful in, for example, the case of Cloud Functions where a source
bundle is generated as part of a plan job.

Closes #72

feat: force commitlint jobs to fail by default

Closes #73

See merge request !87

Add a generic fragment to retrieve Google Secret Manager secrets.

Closes #60

See merge request !86

Excluded trivy rules explained in comments

Closes #70

See merge request !84

Refactor terraform-pipeline template

Closes #68

See merge request !81

These templates should not be being used any more so it is time to remove
them from this repo permanently.

fix: disable terraform_standard_module_structure tflint rule

Closes #52

See merge request !83

chore: update tflint job to be compatible with v0.40.0+ config model

See merge request !82

feat: replace tfsec with trivy

Closes #69

See merge request !80

fix: dind race condition fix

See merge request !79

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