Adjust issue template

@SteveMacenski 
Fix #1102
Clarify which version and how to get version.

.github/ISSUE_TEMPLATE.md

@@ -11,14 +11,12 @@ For Bug report or feature requests, please fill out the relevant category below
 
 - Operating System:
   - <!-- OS and version (e.g. Windows 10, Ubuntu 16.04...) -->
-- Installation type:
-  - <!-- binaries or from source  -->
 - Version or commit hash:
-  - <!-- Output of git rev-parse HEAD, release version, or repos file  -->
+  - <!-- from source: output of `git -C navigation2 rev-parse HEAD
+         apt binaries: output of `dpkg-query --show "ros-$ROS_DISTRO-navigation2"`
+                              or `dpkg-query --show "ros-$ROS_DISTRO-nav2-*`" -->
 - DDS implementation:
-  - <!-- rmw_implementation used (e.g. Fast-RTPS, RTI Connext, etc -->
-- Client library (if applicable):
-  - <!-- e.g. rclcpp, rclpy, or N/A -->
+  - <!-- rmw_implementation used (e.g. Fast-RTPS, RTI Connext, etc.) -->
 
 #### Steps to reproduce issue
 <!-- Detailed instructions on how to reliably reproduce this issue http://sscce.org/