Update pyxdg requirement from <0.27,>=0.26 to >=0.26,<0.29 (#1295)

Updates the requirements on [pyxdg](https://github.com/takluyver/pyxdg) to permit the latest version.
- [Changelog](https://github.com/takluyver/pyxdg/blob/master/ChangeLog)
- [Commits](takluyver/pyxdg@rel-0.26...rel-0.28)

---
updated-dependencies:
- dependency-name: pyxdg
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements.txt

@@ -13,7 +13,7 @@ patool>=1.12,<3.1  # https://github.com/wummel/patool/blob/master/doc/changelog.
 bcrypt>=3.1,<4.3  # https://github.com/pyca/bcrypt/
 chardet>=3.0,<3.1  # https://pypi.python.org/pypi/chardet
 babel==2.12.1  # http://babel.pocoo.org/en/latest/changelog.html
-pyxdg>=0.26,<0.27  # https://freedesktop.org/wiki/Software/pyxdg/
+pyxdg>=0.26,<0.29  # https://freedesktop.org/wiki/Software/pyxdg/
 Jinja2>=2.10,<2.11  # http://jinja.pocoo.org/docs/latest/changelog/
 
 # See https://github.com/pallets/markupsafe/issues/286 but breaking change in