Remove non-functional SSL 2 version code point

As per discussion in #1694, remove SSL 2 for now.  SSL 2 is not actually
implemented, and the version code point is wrong anyway.

SSL 2 uses a version field of 0x0002, not 0x0200.  This is confirmed not
only in the original Netscape spec [1] and RFC draft of the time [2],
but also in major implementations such as OpenSSL [3] and Wireshark [4].

More importantly, SSL 2 has a different record format, without version
field, that is used for both SSL 2 proper, and SSL 2 compatible SSL 3 /
TLS.  For Packet++ to see a SSL 2 version field on the wire, it would
first have to support the SSL 2 record format, and at least one of SSL 2
handshake messages, or SSL 2 compatible SSL 3 or later handshakes.

[1] https://www-archive.mozilla.org/projects/security/pki/nss/ssl/draft02.html
[2] https://datatracker.ietf.org/doc/html/draft-hickman-netscape-ssl-00
[3] https://github.com/openssl/openssl/blob/OpenSSL_0_9_6m/ssl/ssl2.h#L66-L71
[4] https://github.com/wireshark/wireshark/blob/release-4.4/epan/dissectors/packet-tls-utils.h#L266-L277

Packet++/header/SSLCommon.h

@@ -100,8 +100,6 @@ namespace pcpp
 		/// SSL/TLS versions enum
 		enum SSLVersionEnum
 		{
-			/// SSL 2.0
-			SSL2 = 0x0200,
 			/// SSL 3.0
 			SSL3 = 0x0300,
 			/// TLS 1.0

Packet++/src/SSLCommon.cpp

@@ -23,9 +23,6 @@ namespace pcpp
 				return static_cast<SSLVersion::SSLVersionEnum>(m_SSLVersionValue);
 		}
 
-		if (m_SSLVersionValue == 0x200)
-			return SSLVersion::SSL2;
-
 		return SSLVersion::Unknown;
 	}