Bump regex from 2021.8.27 to 2021.8.28

Bumps [regex](https://bitbucket.org/mrabarnett/mrab-regex) from 2021.8.27 to 2021.8.28.
- [Commits](https://bitbucket.org/mrabarnett/mrab-regex/commits)

---
updated-dependencies:
- dependency-name: regex
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

requirements.txt

@@ -17,7 +17,7 @@ PyLink==0.3.3
 pylint==2.9.0
 pyserial==3.5
 pyTelegramBotAPI==3.8.3
-regex==2021.8.27
+regex==2021.8.28
 requests==2.26.0
 six==1.16.0
 toml==0.10.2