[ros-telegram_ros] speficy version which works with old telegram lib

MatthijsBurgh · MatthijsBurgh · commit 0fe1f54693da · 2023-05-30T12:15:10.000+02:00
diff --git a/ros-telegram_ros/install.yaml b/ros-telegram_ros/install.yaml
@@ -2,3 +2,4 @@
   source:
     type: git
     url: https://github.com/tue-robotics/telegram_ros.git
+    version: telegram_lt_20
