Remove End-of-Life distributions. (#12)

Signed-off-by: Chris Lalancette <clalancette@gmail.com>

Author: clalancette

ros_github_scripts/ci_for_pr.py

@@ -32,10 +32,7 @@
 SERVER_RETRIES = 2
 
 ROS_DISTRO_TO_UBUNTU_DISTRO = {
-    'melodic': 'bionic',
     'noetic': 'focal',
-    'foxy': 'focal',
-    'galactic': 'focal',
     'humble': 'jammy',
     'iron': 'jammy',
     'jazzy': 'noble',