feat: initial action implementation

action.yml

@@ -0,0 +1,37 @@
+# SPDX-License-Identifier: EUPL-1.2
+name: "Checkout"
+description: "Checkout a Git repository at a particular version"
+inputs:
+  repository:
+    description: >
+      Repository name with owner. For example, actions/checkout
+    default: ${{ github.server_url }}/${{ github.repository }}.git
+  token:
+    description: >
+      Personal access token (PAT) used to fetch the repository. The PAT is configured
+      with the local git config, which enables your scripts to run authenticated git
+      commands.
+    default: ${{ github.token }}
+  path:
+    description: >
+      Relative path under $GITHUB_WORKSPACE to place the repository
+    default: .
+  ref:
+    description: >
+      The branch, tag or SHA to checkout. When checking out the repository that
+      triggered a workflow, this defaults to the reference or SHA for that
+      event.  Otherwise, uses the default branch.
+    default: ${{ github.ref || github.sha }}
+runs:
+  using: composite
+  steps:
+    - name: Checkout
+      shell: bash
+      run: |
+        export PATH=${{ github.action_path }}/scripts:$PATH
+        checkout.sh
+      env:
+        ACTION_INPUT_TOKEN: ${{ inputs.token }}
+        ACTION_INPUT_REPOSITORY: ${{ inputs.repository }}
+        ACTION_INPUT_PATH: ${{ inputs.path }}
+        ACTION_INPUT_REF: ${{ inputs.ref }}