[PIP] Bump python-gnupg from 0.5.2 to 0.5.4

Bumps [python-gnupg](https://github.com/vsajip/python-gnupg) from 0.5.2 to 0.5.4.
- [Release notes](https://github.com/vsajip/python-gnupg/releases)
- [Changelog](https://github.com/vsajip/python-gnupg/blob/master/release)
- [Commits](vsajip/python-gnupg@0.5.2...0.5.4)

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

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

test_requirements.txt

@@ -1,7 +1,7 @@
 # Test requirements
 pytest>=7.0.0,<=8.3.4
 pytest-subtests>=0.12.0,<=0.14.1
-python-gnupg==0.5.2
+python-gnupg==0.5.4
 
 # No pinning here, because we only switch on optional dependencies here.
 pygments