Bump regex from 2020.10.11 to 2020.10.15

Bumps [regex](https://bitbucket.org/mrabarnett/mrab-regex) from 2020.10.11 to 2020.10.15.
- [Commits](https://bitbucket.org/mrabarnett/mrab-regex/commits)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]

test-requirements.txt

@@ -47,7 +47,7 @@ pyopenssl==19.1.0         # via -r test-requirements.in
 pyparsing==2.4.7          # via packaging
 pytest-cov==2.10.1        # via -r test-requirements.in
 pytest==6.1.1             # via -r test-requirements.in, pytest-cov
-regex==2020.10.11         # via black
+regex==2020.10.15         # via black
 six==1.15.0               # via astroid, cryptography, packaging, pyopenssl
 sniffio==1.2.0            # via -r test-requirements.in
 sortedcontainers==2.2.2   # via -r test-requirements.in