Update install.sh

Minor update because Mininet branch stopped existing

Author: afmurillo

install.sh

@@ -57,7 +57,7 @@ sudo python3 -m pip install .
 
 # Mininet from source
 cd ~
-git clone --depth 1 -b 2.3.1b2 https://github.com/mininet/mininet.git || git -C mininet pull
+git clone --depth 1 -b 2.3.1b4 https://github.com/mininet/mininet.git || git -C mininet pull
 cd mininet
 sudo PYTHON=python3 ./util/install.sh -fnv