examples/noetic-turtlebot3-gazebo: Rename turtlebot3-gazebo example

This commit changes the name of the turtlebot3-gazebo example to
indicate use with a specific ROS distribution.

Signed-off-by: Rodrigo M. Duarte <rodrigo.duarte@ossystems.com.br>

README.md

@@ -17,13 +17,13 @@ Want to use ROS, but don't want to run Ubuntu? This project uses the power of [N
 
 ## Examples
 
-Turtlebot 3 simulation in Gazebo:
+Turtlebot 3 simulation in Gazebo on noetic distro:
 ```
 nix-shell \
   -I nix-ros-overlay=https://github.com/lopsided98/nix-ros-overlay/archive/master.tar.gz \
   --option extra-substituters 'https://ros.cachix.org' \
   --option trusted-public-keys 'cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= ros.cachix.org-1:dSyZxI8geDCJrwgvCOHDoAfOm5sV1wCPjBkKL+38Rvo=' \
-  '<nix-ros-overlay/examples/turtlebot3-gazebo.nix>'
+  '<nix-ros-overlay/examples/noetic-turtlebot3-gazebo.nix>'
 # If not on NixOS, nixGL (https://github.com/guibou/nixGL) is needed for OpenGL support
 roslaunch turtlebot3_gazebo turtlebot3_world.launch
 # Spawn a new nix-shell in a new terminal and then:
@@ -32,9 +32,9 @@ roslaunch turtlebot3_teleop turtlebot3_teleop_key.launch
 
 ### Flakes
 
-With [Flakes enabled][flake], the equivalent of the above is:
+With [Flakes enabled][flake], the equivalent of the above for noetic distro is:
 ```
-nix develop github:lopsided98/nix-ros-overlay#example-turtlebot3-gazebo
+nix develop github:lopsided98/nix-ros-overlay#example-noetic-turtlebot3-gazebo
 # Then use roslaunch commands as above
 ```
 

flake.nix

@@ -18,7 +18,7 @@
       legacyPackages = pkgs.rosPackages;
 
       devShells = {
-        example-turtlebot3-gazebo = import ./examples/turtlebot3-gazebo.nix { inherit pkgs; };
+        example-noetic-turtlebot3-gazebo = import ./examples/noetic-turtlebot3-gazebo.nix { inherit pkgs; };
         example-ros2-basic = import ./examples/ros2-basic.nix { inherit pkgs; };
         example-ros2-gz = import ./examples/ros2-gz.nix { inherit pkgs; };