Bump pycryptodomex from 3.19.0 to 3.21.0 (#1292)

Bumps [pycryptodomex](https://github.com/Legrandin/pycryptodome) from 3.19.0 to 3.21.0.
- [Release notes](https://github.com/Legrandin/pycryptodome/releases)
- [Changelog](https://github.com/Legrandin/pycryptodome/blob/master/Changelog.rst)
- [Commits](Legrandin/pycryptodome@v3.19.0...v3.21.0)

---
updated-dependencies:
- dependency-name: pycryptodomex
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements.txt

@@ -2,7 +2,7 @@ tornado==4.5.3  # http://www.tornadoweb.org/en/stable/releases.html
 psycopg2==2.9.10  # http://initd.org/psycopg/articles/tag/release/
 sqlalchemy>=1.3,<1.4  # http://docs.sqlalchemy.org/en/latest/changelog/index.html
 netifaces>=0.10,<0.12  # https://bitbucket.org/al45tair/netifaces/src/
-pycryptodomex==3.19.0  # https://github.com/Legrandin/pycryptodome/blob/master/Changelog.rst
+pycryptodomex==3.21.0  # https://github.com/Legrandin/pycryptodome/blob/master/Changelog.rst
 psutil>=5.5,<5.6  # https://github.com/giampaolo/psutil/blob/master/HISTORY.rst
 requests==2.32.3  # https://pypi.python.org/pypi/requests
 gevent==24.11.1  # http://www.gevent.org/changelog.html