Update .travis.yml

try suppress warnings - from per1234/arduino-ci-script#1

Author: pa-pa

.travis.yml

@@ -13,6 +13,13 @@ before_install:
   - tar xf arduino-$IDE_VERSION-linux64.tar.xz
   - mv arduino-$IDE_VERSION $HOME/arduino-ide
   - export PATH=$PATH:$HOME/arduino-ide
+# Arduino IDE adds a lot of noise caused by network traffic, trying to firewall it off
+  - sudo iptables -P INPUT DROP
+  - sudo iptables -P FORWARD DROP
+  - sudo iptables -P OUTPUT ACCEPT
+  - sudo iptables -A INPUT -i lo -j ACCEPT
+  - sudo iptables -A OUTPUT -o lo -j ACCEPT
+  - sudo iptables -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
 #  - if [[ "$BOARD" =~ "arduino:samd:" ]]; then
 #      arduino --install-boards arduino:samd;
 #    fi