#4408 add pyopenssl to the dependencies docs

docs/Build/Dependencies.md

@@ -54,6 +54,7 @@ See [Network](../Network/README.md)
 | [lz4](https://github.com/lz4/lz4)                                  | https://github.com/lz4/lz4/releases                     | [packet compression](PacketEncoding)                           | both                | Strongly recommended                                 |
 | [aioquic](https://github.com/aiortc/aioquic)                       | https://pypi.org/project/aioquic/                       | low level network protocol                                     | both                | [quic](https://github.com/Xpra-org/xpra/issues/3376) |
 | [python-cryptography](https://cryptography.io/en/latest/)          | https://pypi.python.org/pypi/cryptography               | [Encryption](Encryption)                                       | both                |                                                      |
+| [pyopenssl](https://github.com/pyca/pyopenssl)                     | https://pypi.org/project/pyOpenSSL/                     | [Encryption](Encryption)                                       | both                |                                                      |
 | [python-zeroconf](https://github.com/jstasiak/python-zeroconf)     | https://pypi.org/project/zeroconf/                      | [Multicast DNS](Multicast-DNS) session publishing and browsing | both                |                                                      |
 | [python-netifaces](http://alastairs-place.net/projects/netifaces/) | https://pypi.python.org/pypi/netifaces                  | [Multicast DNS](Multicast-DNS) session publishing              | server              |                                                      |
 | [dbus-python](https://pypi.python.org/pypi/dbus-python/)           | https://dbus.freedesktop.org/releases/dbus-python/      | desktop integration, server control interface                  | both                | not applicable to MS Windows or Mac OSX              |