Remove Iron workflows and from README (#230)

Since Iron is now EOL, we will not add any further changes to Iron.

Author: urfeex

.github/mergify.yml

@@ -9,14 +9,3 @@ pull_request_rules:
           - humble
         labels:
           - humble
-
-  - name: Backport to iron branch
-    conditions:
-      - base=rolling
-      - label=backport-iron
-    actions:
-      backport:
-        branches:
-          - iron
-        labels:
-          - iron

.github/workflows/iron-binary-main.yml

@@ -7,7 +7,6 @@ This repository contains description files and meshes for *Universal Robots* man
 ROS2 Distro | Branch | Build status | Released packages
 :---------: | :----: | :----------: | :---------------:
 **Humble** | [`humble`](https://github.com/UniversalRobots/Universal_Robots_ROS2_Description/tree/humble) | [![Build Status](https://build.ros2.org/job/Hbin_uJ64__ur_description__ubuntu_jammy_amd64__binary/badge/icon)](https://build.ros2.org/job/Hbin_uJ64__ur_description__ubuntu_jammy_amd64__binary/) | [ur_description](https://index.ros.org/p/ur_description/#humble)
-**Iron** | [`iron`](https://github.com/UniversalRobots/Universal_Robots_ROS2_Description/tree/iron) | [![Build Status](https://build.ros2.org/job/Ibin_uJ64__ur_description__ubuntu_jammy_amd64__binary/badge/icon)](https://build.ros2.org/job/Ibin_uJ64__ur_description__ubuntu_jammy_amd64__binary/) | [ur_description](https://index.ros.org/p/ur_description/#iron)
 **Jazzy** | [`rolling`](https://github.com/UniversalRobots/Universal_Robots_ROS2_Description/tree/rolling) | [![Build Status](https://build.ros2.org/job/Jbin_uN64__ur_description__ubuntu_noble_amd64__binary/badge/icon)](https://build.ros2.org/job/Jbin_uN64__ur_description__ubuntu_noble_amd64__binary/) | [ur_description](https://index.ros.org/p/ur_description/#jazzy)
 **Rolling** | [`rolling`](https://github.com/UniversalRobots/Universal_Robots_ROS2_Description/tree/rolling) | [![Build Status](https://build.ros2.org/job/Rbin_uN64__ur_description__ubuntu_noble_amd64__binary/badge/icon)](https://build.ros2.org/job/Rbin_uN64__ur_description__ubuntu_noble_amd64__binary/)| [ur_description](https://index.ros.org/p/ur_description/#rolling)
 

.github/workflows/iron-binary-testing.yml

@@ -7,14 +7,12 @@ upstream changes some pipelines might turn red temporarily which can be expected
   <tr>
     <th></th>
     <th>Humble</th>
-    <th>Iron</th>
     <th>Jazzy</th>
     <th>Rolling</th>
   </tr>
   <tr>
     <th>Branch</th>
     <td><a href="https://github.com/UniversalRobots/Universal_Robots_ROS2_Description/tree/humble">humble</a></td>
-    <td><a href="https://github.com/UniversalRobots/Universal_Robots_ROS2_Description/tree/iron">iron</a></td>
     <td><a href="https://github.com/UniversalRobots/Universal_Robots_ROS2_Description/tree/rolling">rolling</a></td>
     <td><a href="https://github.com/UniversalRobots/Universal_Robots_ROS2_Description/tree/rolling">rolling</a></td>
   </tr>
@@ -30,16 +28,6 @@ upstream changes some pipelines might turn red temporarily which can be expected
               alt="Humble Binary Testing"/>
       </a> <br />
     </td>
-    <td>
-      <a href="https://github.com/UniversalRobots/Universal_Robots_ROS2_Description/actions/workflows/iron-binary-main.yml?query=event%3Aschedule++">
-         <img src="https://github.com/UniversalRobots/Universal_Robots_ROS2_Description/actions/workflows/iron-binary-main.yml/badge.svg?event=schedule"
-              alt="Iron Binary Main"/>
-      </a> <br />
-      <a href="https://github.com/UniversalRobots/Universal_Robots_ROS2_Description/actions/workflows/iron-binary-testing.yml?query=event%3Aschedule++">
-         <img src="https://github.com/UniversalRobots/Universal_Robots_ROS2_Description/actions/workflows/iron-binary-testing.yml/badge.svg?event=schedule"
-              alt="Iron Binary Testing"/>
-      </a> <br />
-    </td>
     <td>
       <a href="https://github.com/UniversalRobots/Universal_Robots_ROS2_Description/actions/workflows/jazzy-binary-main.yml?query=event%3Aschedule++">
          <img src="https://github.com/UniversalRobots/Universal_Robots_ROS2_Description/actions/workflows/jazzy-binary-main.yml/badge.svg?event=schedule"
@@ -66,9 +54,6 @@ upstream changes some pipelines might turn red temporarily which can be expected
     <td>
       <a href='https://build.ros2.org/job/Hbin_uJ64__ur_description__ubuntu_jammy_amd64__binary/'><img src='https://build.ros2.org/job/Hbin_uJ64__ur_description__ubuntu_jammy_amd64__binary/badge/icon?subject=uJ64_ur_description'></a>
     </td>
-    <td>
-      <a href='https://build.ros2.org/job/Ibin_uJ64__ur_description__ubuntu_jammy_amd64__binary/'><img src='https://build.ros2.org/job/Ibin_uJ64__ur_description__ubuntu_jammy_amd64__binary/badge/icon?subject=uJ64_ur_description'></a>
-    </td>
     <td>
       <a href='https://build.ros2.org/job/Jbin_uN64__ur_description__ubuntu_noble_amd64__binary/'><img src='https://build.ros2.org/job/Jbin_uN64__ur_description__ubuntu_noble_amd64__binary/badge/icon?subject=uN64_ur_description'></a>
     </td>