The test was modifying a fixture, and this fixture is not in .gitignore.
The consequence is that if there were errors, the fixture was changed and developers would potentially commit an invalid fixture due to this.
This PR leverages the previous change introduced in #236 to use envvars for templating YML filepaths

A Pytest fixture modified a DAG YAML file, which is not in .gitignore.

The consequence is that if there were errors, the fixture was changed
and developers would potentially commit an invalid fixture - that would
be invalid in the CI.

This PR leverages the previous change introduced in #236 to use envvars
for templating YML filepaths..

### Added
- Support using envvar in config YAML by @tatiana in #236
- **Callback improvements**
- Support installed code via python callable string by @john-drews in
#221
- Add `callback_file` & `callback_name` to `default_args` DAG level by
@subbota19 in #218
- Cast callbacks to functions when set with `default_args` on TaskGroups
by @Baraldo and @pankajastro in #235

- **Telemetry**
- For more information, please, read the [Privacy
Notice](https://github.com/astronomer/dag-factory/blob/main/PRIVACY_NOTICE.md#collection-of-data).
  - Add scarf to readme for website analytics by @cmarteepants in #219
- Support telemetry during DAG parsing emitting data to Scarf by
@tatiana in #250.

### Fixed
- Build DAGs when tehre is an invalid YAML in the DAGs folder by @quydx
and @tatiana in #184

### Others
- Development tools
  - Fix make docker-run by @pankajkoti in #249
  - Add vim dot files to .gitignore by @tatiana in #228
  - Use Hatchling to modern package building by @kaxil in #208
- CI
  - Fix static check failures in PR #218 by @pankajkoti in #251
  - Fix pre-commit checks by @tatiana in #247
  - Remove tox and corresponding build jobs in CI by @pankajkoti in #248
- Install Airflow with different versions in the CI by @pankajkoti in
#237
  - Run pre-commit hooks on all existing files by @pankajkoti in #245
  - Add Python 3.11 and 3.12 to CI test pipeline by @pankajkoti in #229
- Tests
  - Fix duplicate test name by @pankajastro in #234
  - Add static check by @pankajastro in #231
  - Fix running tests locally (outside the CI) by @tatiana in #227
  - Add the task_2 back to dataset example by @cmarteepants in #204
  - Remove unnecessary config line by @jlaneve in #202
- Documentation
  - Update the license from MIT to Apache 2.0 by @pankajastro in #191
- Add registration icon and links to Airflow references by @cmarteepants
in #190
  - Update quickstart and add feature examples by @cmarteepants #189

### Breaking changes
- Removed support for Python 3.7
- The license was changed from MIT to Apache 2.0

Closes: #217