added open source packet sender to the book of knowledge. (#142)

added open source packet sender to the book of knowledge.

README.md

@@ -395,6 +395,7 @@ Only main chapters:
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://www.wireshark.org/"><b>Wireshark</b></a> - is the world’s foremost and widely-used network protocol analyzer.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://www.ettercap-project.org/"><b>Ettercap</b></a> - is a comprehensive network monitor tool.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://etherape.sourceforge.io/"><b>EtherApe</b></a> - is a graphical network monitoring solution.<br>
+&nbsp;&nbsp;:small_orange_diamond: <a href="https://packetsender.com/"><b>Packet Sender</b></a> - is a networking utility for packet generation and built-in UDP/TCP/SSL client and servers.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://jmeter.apache.org/"><b>JMeter™</b></a> - open source software to load test functional behavior and measure performance.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/locustio/locust"><b>locust</b></a> - scalable user load testing tool written in Python.<br>
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