Ubuntu 20 Deprecation changes (#11748)

* Ubuntu 20 Deprecation updates

* Updating .md files

* Update announcement.yml

* Update bug-report.yml

* Update tool-request.yml

* Updating merge conflicts

* Updating .md files

* Updating merge conflicts

* Resolved merge conflicts

---------

Co-authored-by: Prabhat kumar <prabhatkumar59@Prabhats-Laptop.local>

.github/workflows/ubuntu2004.yml

@@ -1,20 +0,0 @@
-name: Trigger Ubuntu20.04 CI
-run-name: Ubuntu20.04 - ${{ github.event.pull_request.title }}
-
-on:
-  pull_request_target:
-    types: labeled
-    paths:
-    - 'images/ubuntu/**'
-
-defaults:
-  run:
-    shell: pwsh
-
-jobs:
-  Ubuntu_2004:
-    if: github.event.label.name == 'CI ubuntu-all' || github.event.label.name == 'CI ubuntu-2004'
-    uses: ./.github/workflows/trigger-ubuntu-win-build.yml
-    with:
-      image_type: 'ubuntu2004'
-    secrets: inherit