IMPROVEMENT: add markdownlint and markdown-link-check actions

Author: amilcarlucas

.github/workflows/markdown-link-check.yml

@@ -0,0 +1,14 @@
+name: Check Markdown links
+
+on: push
+
+jobs:
+  markdown-link-check:
+    runs-on: ubuntu-latest
+    steps:
+
+    - name: Checkout
+      uses: actions/checkout@v4
+
+    - name: Check links
+      uses: gaurav-nelson/github-action-markdown-link-check@v1

.github/workflows/markdown-lint.yml

@@ -0,0 +1,16 @@
+name: Lint Markdown
+
+on: push
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: lint markdown
+        uses: DavidAnson/markdownlint-cli2-action@v18
+        with:
+          globs: '**/*.md'

README.md

@@ -11,7 +11,8 @@ SPDX-License-Identifier: GPL-3.0-or-later
 | [![Pylint](https://github.com/ArduPilot/MethodicConfigurator/actions/workflows/pylint.yml/badge.svg)](https://github.com/ArduPilot/MethodicConfigurator/actions/workflows/pylint.yml) | [![Codacy Badge](https://app.codacy.com/project/badge/Grade/720794ed54014c58b9eaf7a097a4e98e)](https://app.codacy.com/gh/amilcarlucas/MethodicConfigurator/dashboard?utm_source=gh&utm_medium=referral&utm_content=&utm_campaign=Badge_grade) | [![Python unit-tests](https://github.com/ArduPilot/MethodicConfigurator/actions/workflows/unit-tests.yml/badge.svg)](https://github.com/ArduPilot/MethodicConfigurator/actions/workflows/unit-tests.yml) | [![pages-build-deployment](https://github.com/ArduPilot/MethodicConfigurator/actions/workflows/pages/pages-build-deployment/badge.svg)](https://github.com/ArduPilot/MethodicConfigurator/actions/workflows/pages/pages-build-deployment) | [![Average time to resolve an issue](http://isitmaintained.com/badge/resolution/ArduPilot/MethodicConfigurator.svg)](http://isitmaintained.com/project/ArduPilot/MethodicConfigurator) |
 | [![test Python cleanliness](https://github.com/ArduPilot/MethodicConfigurator/actions/workflows/ruff.yml/badge.svg)](https://github.com/ArduPilot/MethodicConfigurator/actions/workflows/ruff.yml) | [![OpenSSF Best Practices](https://www.bestpractices.dev/projects/9101/badge)](https://www.bestpractices.dev/projects/9101) | [![Pytest unittests](https://github.com/ArduPilot/MethodicConfigurator/actions/workflows/unittests.yml/badge.svg)](https://github.com/ArduPilot/MethodicConfigurator/actions/workflows/unittests.yml) | [![Upload MethodicConfigurator Package](https://github.com/ArduPilot/MethodicConfigurator/actions/workflows/python-publish.yml/badge.svg)](https://github.com/ArduPilot/MethodicConfigurator/actions/workflows/python-publish.yml) | [![Percentage of issues still open](http://isitmaintained.com/badge/open/ArduPilot/MethodicConfigurator.svg)](http://isitmaintained.com/project/ArduPilot/MethodicConfigurator) |
 | [![mypy](https://github.com/ArduPilot/MethodicConfigurator/actions/workflows/mypy.yml/badge.svg)](https://github.com/ArduPilot/MethodicConfigurator/actions/workflows/mypy.yml) | [![Known Vulnerabilities](https://snyk.io/test/github/amilcarlucas/MethodicConfigurator/badge.svg)](https://snyk.io/test/github/amilcarlucas/MethodicConfigurator) | [![codecov](https://codecov.io/github/amilcarlucas/MethodicConfigurator/graph/badge.svg?token=76P928EOL2)](https://codecov.io/github/amilcarlucas/MethodicConfigurator) | [![Windows Build](https://github.com/ArduPilot/MethodicConfigurator/actions/workflows/windows_build.yml/badge.svg)](https://github.com/ArduPilot/MethodicConfigurator/actions/workflows/windows_build.yml) | |
-| | [![Code Climate](https://codeclimate.com/github/amilcarlucas/MethodicConfigurator.png)](https://codeclimate.com/github/amilcarlucas/MethodicConfigurator) | [![Coverity Scan Build Status](https://scan.coverity.com/projects/30346/badge.svg)](https://scan.coverity.com/projects/ardupilot-methodic-configurator) | | |
+| [![markdown](https://github.com/ArduPilot/MethodicConfigurator/actions/workflows/markdown-lint.yml/badge.svg)](https://github.com/ArduPilot/MethodicConfigurator/actions/workflows/markdown-lint.yml) | [![Code Climate](https://codeclimate.com/github/amilcarlucas/MethodicConfigurator.png)](https://codeclimate.com/github/amilcarlucas/MethodicConfigurator) | [![Coverity Scan Build Status](https://scan.coverity.com/projects/30346/badge.svg)](https://scan.coverity.com/projects/ardupilot-methodic-configurator) | | |
+| [![md-link-check](https://github.com/ArduPilot/MethodicConfigurator/actions/workflows/markdown-link-check.yml/badge.svg)](https://github.com/ArduPilot/MethodicConfigurator/actions/workflows/markdown-link-check.yml) | | | | |
 
 Amilcar Lucas's ArduPilot Methodic Configurator is a software that semi-automates a
 [clear, proven and safe configuration sequence for ArduCopter drones](https://ardupilot.github.io/MethodicConfigurator/TUNING_GUIDE_ArduCopter).