fix: update all runner images to ubuntu-latest (#3001)

## Description

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> Please include a summary of the change and which issue is fixed.
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Fixes #123
Fixes #456
Closes #123
Closes #456
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## Pipeline Reference

<!-- Insert your Pipeline Status Badge below -->

| Pipeline |
| -------- |
| [![.Platform - Run CI
tests](https://github.com/Azure/bicep-registry-modules/actions/workflows/platform.ci-tests.yml/badge.svg?branch=users%2Feriqua%2Fubuntu-latest)](https://github.com/Azure/bicep-registry-modules/actions/workflows/platform.ci-tests.yml)
|
| [![.Platform - Clean up deployment
history](https://github.com/Azure/bicep-registry-modules/actions/workflows/platform.deployment.history.cleanup.yml/badge.svg?branch=users%2Feriqua%2Fubuntu-latest)](https://github.com/Azure/bicep-registry-modules/actions/workflows/platform.deployment.history.cleanup.yml)
|
|
[![avm.res.container-service.managed-cluster](https://github.com/Azure/bicep-registry-modules/actions/workflows/avm.res.container-service.managed-cluster.yml/badge.svg?branch=users%2Feriqua%2Fubuntu-latest)](https://github.com/Azure/bicep-registry-modules/actions/workflows/avm.res.container-service.managed-cluster.yml)
|

## Type of Change

<!-- Use the checkboxes [x] on the options that are relevant. -->

- [ ] Update to CI Environment or utilities (Non-module affecting
changes)
- [ ] Azure Verified Module updates:
- [ ] Bugfix containing backwards-compatible bug fixes, and I have NOT
bumped the MAJOR or MINOR version in `version.json`:
- [ ] Someone has opened a bug report issue, and I have included "Closes
#{bug_report_issue_number}" in the PR description.
- [ ] The bug was found by the module author, and no one has opened an
issue to report it yet.
- [ ] Feature update backwards compatible feature updates, and I have
bumped the MINOR version in `version.json`.
- [ ] Breaking changes and I have bumped the MAJOR version in
`version.json`.
  - [ ] Update to documentation

## Checklist

- [ ] I'm sure there are no other open Pull Requests for the same
update/change
- [ ] I have run `Set-AVMModule` locally to generate the supporting
module files.
- [ ] My corresponding pipelines / checks run clean and green without
any errors or warnings

<!-- Please keep up to date with the contribution guide at
https://aka.ms/avm/contribute/bicep -->

.github/workflows/avm.res.container-service.managed-cluster.yml

@@ -46,7 +46,7 @@ jobs:
   #   Initialize pipeline   #
   ###########################
   job_initialize_pipeline:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     name: "Initialize pipeline"
     steps:
       - name: "Checkout"

.github/workflows/avm.res.web.hosting-environment.yml

@@ -46,7 +46,7 @@ jobs:
   #   Initialize pipeline   #
   ###########################
   job_initialize_pipeline:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     name: "Initialize pipeline"
     steps:
       - name: "Checkout"

.github/workflows/platform.ci-tests.yml

@@ -46,7 +46,7 @@ jobs:
   #   Removal   #
   ###############
   job_run_tests:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     name: "Run CI tests"
     needs:
       - job_initialize_pipeline

.github/workflows/platform.deployment.history.cleanup.yml

@@ -48,7 +48,7 @@ jobs:
   #   Removal   #
   ###############
   job_cleanup_subscription_deployments:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     name: "Remove Subscription deployments"
     needs:
       - job_initialize_pipeline
@@ -87,7 +87,7 @@ jobs:
           azPSVersion: "latest"
 
   job_cleanup_managementGroup_deployments:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     name: "Remove Management Group deployments"
     needs:
       - job_initialize_pipeline