Added GitHub action to check links

Author: joachimmetz

docs/conf.py

@@ -55,3 +55,11 @@
 
 # Level of headers to automatically generate label "slugs" (heading anchors).
 myst_heading_anchors = 3
+
+
+# -- Options for linkcheck ---------------------------------------------------
+
+linkcheck_request_headers = {
+    'https://docs.github.com/': {
+        'User-Agent': 'Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:24.0) Gecko/20100101 Firefox/24.0'}
+}