Fix wrong file extension of GitHub action (grafana#42)

* Fix wrong file extension of GH action

* Do retries on the link check

* Try fixing links

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

@@ -22,4 +22,4 @@ jobs:
       run: sudo npm install -g markdown-link-check
 
     - name: run markdown-link-check
-      run: "find . -name '*.md' -print0 | xargs -0 -n1 markdown-link-check"
+      run: "find . -name '*.md' -print0 | xargs -0 -n1 markdown-link-check --config .markdown_link_check_config.json"

.markdown_link_check_config.json

@@ -0,0 +1,5 @@
+{
+  "retryOn429": true,
+  "timeout": "30s",
+  "aliveStatusCodes": [200, 403]
+}

README.md

@@ -7,10 +7,12 @@
 
 # Grafana OpenTelemetry distribution for .NET
 
+<!-- markdown-link-check-disable -->
 [![Build](https://github.com/grafana/grafana-opentelemetry-dotnet/actions/workflows/unit-tests.yml/badge.svg?branch=main)](https://github.com/grafana/grafana-opentelemetry-dotnet/actions/workflows/unit-tests.yml)
 [![Nuget](https://img.shields.io/nuget/v/Grafana.OpenTelemetry.svg)](https://www.nuget.org/profiles/Grafana)
 [![SDK](https://img.shields.io/badge/otel--sdk-1.6.0-blue?style=flat&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-dotnet)
 [![Slack](https://img.shields.io/badge/join%20slack-%23app--o11y-brightgreen.svg?logo=slack)](https://grafana.slack.com/archives/C05E87XRK3J)
+<!-- markdown-link-check-enable -->
 
 ## About