Bump pyyaml from 5.3.1 to 5.4

Bumps [pyyaml](https://github.com/yaml/pyyaml) from 5.3.1 to 5.4.
- [Release notes](https://github.com/yaml/pyyaml/releases)
- [Changelog](https://github.com/yaml/pyyaml/blob/master/CHANGES)
- [Commits](yaml/pyyaml@5.3.1...5.4)

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

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

Author: dependabot[bot]

requirements.txt

@@ -49,7 +49,7 @@ PyNaCl==1.3.0
 python-dateutil==2.8.1
 python3-indy==1.16.0
 pytz==2021.1
-PyYAML==5.3.1
+PyYAML==5.4
 qrcode==6.1
 requests==2.23.0
 six==1.16.0