Bump reportlab from 3.6.3 to 3.6.12

Bumps [reportlab](http://www.reportlab.com/) from 3.6.3 to 3.6.12.

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

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

requirements.txt

@@ -131,7 +131,7 @@ pyyaml==6.0
     #   rst2pdf (setup.py)
 qrcode==7.3.1
     # via pyhanko
-reportlab==3.6.3
+reportlab==3.6.12
     # via
     #   rst2pdf (setup.py)
     #   svglib