fix(ci): add markdown linter and adapt renovate packageRule

.gitea/workflows/markdown-linters.yaml

@@ -0,0 +1,46 @@
+name: Markdown linter
+
+on:
+  pull_request:
+    paths: [ "**/*.md" ]
+    types: [ "opened", "reopened", "synchronize" ]
+  push:
+    branches:
+    - '**'
+    paths: [ "**/*.md" ]
+    tags-ignore:
+    - '**'
+  workflow_dispatch: {}
+
+jobs:
+  markdown-link-checker:
+    container:
+      image: docker.io/library/node:24.10.0-alpine
+    runs-on:
+    - ubuntu-latest
+    steps:
+    - name: Install tooling
+      run: |
+        apk update
+        apk add git npm
+    - uses: actions/checkout@v5.0.0
+    - name: Verify links in markdown files
+      run: |
+        npm install
+        npm run readme:link
+
+  markdown-lint:
+    container:
+      image: docker.io/library/node:24.10.0-alpine
+    runs-on:
+    - ubuntu-latest
+    steps:
+    - name: Install tooling
+      run: |
+        apk update
+        apk add git
+    - uses: actions/checkout@v5.0.0
+    - name: Lint markdown files
+      run: |
+        npm install
+        npm run readme:lint

README.md

@@ -6,8 +6,9 @@ This project contains all sources to build the container image `git.cryptic.syst
 primary goal of this project is to package the binary `docker-compose` as container image. The source code of the binary
 can be found in the upstream project of [docker/compose](https://github.com/docker/compose).
 
-The workflow or how `docker-compose` can in general be used is documented [here](https://docs.docker.com/compose/).
+The workflow or how `docker-compose` can in general be used is documented at
-Nevertheless, here are some examples of how to use the container image.
+[docs.docker.com](https://docs.docker.com/compose/). Nevertheless, here are some examples of how to use the container
+image.
 
 ```bash
 IMAGE_VERSION=2.34.0

renovate.json

@@ -4,7 +4,7 @@
     {
       "fileMatch": ["^README\\.md$"],
       "matchStrings": [
-        "VERSION=(?<currentValue>.*)"
+        "IMAGE_VERSION=(?<currentValue>.*)"
       ],
       "depNameTemplate": "volker.raschek/docker-compose",
       "datasourceTemplate": "docker",