DOC: proxy-protocol: fix wrong byte in provided example

There was a mistake in the example of proxy-proto frame
provided, it cannot end with 0x02 but only 0x20 or 0x21
since the version is in the upper 4 bits and the lower ones
are 0 for LOCAL or 1 for PROXY, hence the example should be:

  \x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A\x20

Thanks to Bram Grit for reporting this mistake.

(cherry picked from commit e008402972e58ab99506bbbbf4d540a21f5be465)
Signed-off-by: Willy Tarreau <w@1wt.eu>
(cherry picked from commit 687176f6d661e7882fd3b76427f2fe9a53e7bc1e)
Signed-off-by: Willy Tarreau <w@1wt.eu>
(cherry picked from commit 663e673a3c9d51aaa5a47e9a39b754616c7c7219)
Signed-off-by: Willy Tarreau <w@1wt.eu>
(cherry picked from commit 7248b95e79df11e9c596cb610d940440f9cd6cb4)
Signed-off-by: Willy Tarreau <w@1wt.eu>
diff --git a/doc/proxy-protocol.txt b/doc/proxy-protocol.txt
index 4d49d5c..fac0331 100644
--- a/doc/proxy-protocol.txt
+++ b/doc/proxy-protocol.txt
@@ -500,7 +500,7 @@
     - if the incoming byte count is 16 or above and the 13 first bytes match
       the protocol signature block followed by the protocol version 2 :
 
-           \x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A\x02
+           \x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A\x20
 
     - otherwise, if the incoming byte count is 8 or above, and the 5 first
       characters match the US-ASCII representation of "PROXY" then the protocol