Flask-compress

- When compression is enabled, *accept-encoding* is always added to the `Vary` header, fixes [28](https://github.com/colour-science/flask-compress/issues/28)

- Automate the release process with GitHub Actions
- Use `setuptools_scm` to manage package versions
- The layout is now an actual package rather than a single module
- Clean up unused files

- Add support for the `identity` value in *accept-encoding*, fixes [19](https://github.com/colour-science/flask-compress/issues/19)

- Support ETag header as defined in *RFC7232* [17](https://github.com/colour-science/flask-compress/pull/17)
- Implement per-view compression [14](https://github.com/colour-science/flask-compress/pull/14)

- The following parameters to control Brotli compression are now available: [10](https://github.com/colour-science/flask-compress/pull/10)
- `COMPRESS_BR_MODE`
- `COMPRESS_BR_LEVEL`
- `COMPRESS_BR_WINDOW`
- `COMPRESS_BR_BLOCK`
- Add deflate support, with `COMPRESS_DEFLATE_LEVEL` to control compression level (default is `-1`) [8](https://github.com/colour-science/flask-compress/pull/8)
- The default quality level for Brotli is now `4`, which provides compression comparable to `gzip` at the default setting, while reducing the time required versus the Brotli default of `11`

- Support for multiple compression algorithms and quality factors [7](https://github.com/colour-science/flask-compress/pull/7)
- Modified default compression settings to use Brotli when available before `gzip`