Update .travis.yml: trusty->bionic (#796)

* Update .travis.yml

* Fix py3 setup

.travis.yml

@@ -1,5 +1,5 @@
 sudo: required
-dist: trusty
+dist: bionic
 language: python
 cache:
     - pip

setup.sh

@@ -22,7 +22,7 @@ install_apt() {
     sudo apt-get update || true
     # This breaks Ubuntu 20.04, but is probably still needed for older version
     sudo apt-get -y install python-pip || true
-    sudo apt-get -y install git gdb python-dev python3-dev python3-pip libglib2.0-dev libc6-dbg
+    sudo apt-get -y install git gdb python-dev python3-dev python3-pip python3-setuptools libglib2.0-dev libc6-dbg
 
     if uname -m | grep x86_64 > /dev/null; then
         sudo apt-get -y install libc6-dbg:i386 || true