Add GitHub CI action to run linkchecker

.github/linkchecker/linkchecker.conf

@@ -0,0 +1,8 @@
+[output]
+log=html
+
+[checking]
+sslverify=0
+
+[filtering]
+checkextern=1

.github/workflows/linkchecker.yml

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+name: Check links in the README
+
+on: [push, pull_request]
+
+jobs:
+  LinkChecker:
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
+      - uses: awalsh128/cache-apt-pkgs-action@latest
+        with:
+          packages: pandoc
+
+      - name: Convert Markdown to HTML format
+        run: pandoc README.md --standalone --output README.html
+
+      - name: Set up Python 3.9
+        uses: actions/setup-python@v4
+        with:
+          python-version: '3.9'
+
+      - run: pip install linkchecker --user
+
+      - name: Link Checker
+        run: linkchecker README.html --config .github/linkchecker/linkchecker.conf --file-output html/utf-8/report.html
+
+      - run: cat report.html >> ${GITHUB_STEP_SUMMARY}
+        if: success() || failure()

.github/workflows/lint.yml

@@ -1,12 +0,0 @@
-name: lint
-
-on: [push, pull_request]
-
-jobs:
-  lint:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v3
-        with:
-          fetch-depth: 0
-      - run: npx awesome-lint

report.html

@@ -0,0 +1,39 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
+<title>LinkChecker 10.2.1</title>
+<style type="text/css">
+<!--
+ h2 { font-family: Verdana,sans-serif; font-size: 22pt; font-weight: bold; }
+ body { font-family: Arial,sans-serif; font-size: 11pt; background-color: #fff7e5; }
+ td { font-family: Arial,sans-serif; font-size: 11pt; }
+ code { font-family: Courier; }
+ a:link {color: #191c83;}
+ a:visited {color: #191c83;}
+ a:active {color: #191c83;}
+ a:hover { color: #34a4ef; }
+ table { border-collapse:collapse; }
+ table, th, td { border: 1px solid black; padding: 2px; }
+ td.url { background-color: #dcd5cf }
+ td.valid { background-color: #3ba557 }
+ td.error { background-color: #db4930 }
+ td.warning { background-color: #e0954e }
+-->
+</style>
+</head>
+<body>
+<!-- Generated by LinkChecker 10.2.1 --><h2>LinkChecker 10.2.1</h2><br/><blockquote>LinkChecker comes with ABSOLUTELY NO WARRANTY!
+This is free software, and you are welcome to redistribute it under
+certain conditions. Look at the file `LICENSE' within this distribution.<br/><br/>Start checking at 2023-07-20 10:35:59+002
+<br/><br/><i>Statistics</i><br/>
+No statistics available since no URLs were checked.
+<br/>
+<br/>
+That's it. 0 links checked. 0 warnings found. 0 errors found.
+<br/>
+Stopped checking at 2023-07-20 10:35:59+002 (0.00 seconds)
+</blockquote><br/><hr><small>LinkChecker 10.2.1, Copyright &copy; 2000-2016 Bastian&nbsp;Kleineidam, 2010-2022 LinkChecker&nbsp;Authors<br/>
+Read the documentation at <a href="https://linkchecker.github.io/linkchecker/" target="_top">https://linkchecker.github.io/linkchecker/</a>.<br/>
+Write comments and bugs to <a href="https://github.com/linkchecker/linkchecker/issues">https://github.com/linkchecker/linkchecker/issues</a>.<br/>
+</small></body></html>