Run action without Docker

Move to composite action as described in
https://dev.to/github/build-your-own-github-action-without-a-docker-container-1eic.
The goal is to improve runtime by avoiding to build a Docker image

action.yml

@@ -18,8 +18,18 @@ inputs:
     default: false
     required: false
 runs:
-  using: "docker"
-  image: "Dockerfile"
+  using: "composite"
+  steps:
+    - name: install lychee
+      run: |
+        curl -LO 'https://github.com/lycheeverse/lychee/releases/download/v0.9.0/lychee-v0.9.0-x86_64-unknown-linux-gnu.tar.gz'
+        tar -xvzf lychee-v0.9.0-x86_64-unknown-linux-gnu.tar.gz
+        chmod 755 lychee
+      shell: bash
+    - run: |
+        source entrypoint.sh
+      shell: bash
+
 branding:
   icon: "external-link"
   color: "purple"

entrypoint.sh

@@ -1,6 +1,8 @@
 #!/bin/bash -l
 set -uxo pipefail
 
+env
+
 LYCHEE_TMP="/tmp/lychee/out.md"
 GITHUB_WORKFLOW_URL="https://github.com/${GITHUB_REPOSITORY}/actions/runs/${GITHUB_RUN_ID}?check_suite_focus=true"