Add python-is-python3 to INSTALL-UBUNTU's list of packages

See #5786

Author: magnumripper

doc/INSTALL-UBUNTU

@@ -149,7 +149,7 @@ build CPU fallback chains for any x86-64 CPU.
 
     Install most of them as Ubuntu packages (if you like):
 
-    sudo apt-get -y install python3-pycryptodome python3-scapy python3-parsimonious python3-asn1crypto python3-dpkt python3-cbor2 python3-cryptography python3-simplejson python3-idna python3-lxml python3-ldap3 python3-olefile python3-bsddb3
+    sudo apt-get -y install python-is-python3 python3-pycryptodome python3-scapy python3-parsimonious python3-asn1crypto python3-dpkt python3-cbor2 python3-cryptography python3-simplejson python3-idna python3-lxml python3-ldap3 python3-olefile python3-bsddb3
 
     Alternatively, use pip3 to install all of them into a virtual environment: