Bump python-magic from 0.4.15 to 0.4.18 in /src/requirements (#530)

Bumps [python-magic](https://github.com/ahupp/python-magic) from 0.4.15 to 0.4.18.
- [Release notes](https://github.com/ahupp/python-magic/releases)
- [Commits](https://github.com/ahupp/python-magic/commits)

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

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

src/requirements/production.txt

@@ -29,7 +29,7 @@ pipdeptree==0.13.2
 psycopg2-binary==2.8.5
 pyOpenSSL==19.1.0
 PyPDF2==1.26.0
-python-magic==0.4.15
+python-magic==0.4.18
 service-identity==18.1.0
 Unidecode==1.1.1
 wheel==0.34.2