build: use Justfile as command runner

.env

@@ -0,0 +1,11 @@
+# Variables used by the Justfile
+
+# Godot
+
+GODOT_VERSION=4.1.2
+
+# Game
+
+GAME_NAME=Marble
+GAME_VERSION=1.4.2
+GAME_ITCHIO_KEY=marble

.github/workflows/release-packaging.yml

@@ -0,0 +1,89 @@
+name: Release Packaging
+
+on:
+  push:
+  workflow_dispatch:
+
+env:
+  BRANCH_NAME: ${{ github.head_ref || github.ref_name }}
+
+jobs:
+  check:
+    runs-on: ubuntu-22.04
+    timeout-minutes: 30
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: extractions/setup-just@v1
+
+      - name: Load dotenv
+        run: just ci-load-dotenv
+
+      - name: Check
+        run: just fmt
+
+      - name: Ensure version is equal to tag
+        if: startsWith(github.ref, 'refs/tags/')
+        run: |
+          [ "${{ env.game_version }}" == "${{ env.BRANCH_NAME }}" ] || exit 2
+  build:
+    runs-on: ubuntu-22.04
+    timeout-minutes: 30
+    needs: [check]
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: extractions/setup-just@v1
+
+      - name: Load dotenv
+        run: just ci-load-dotenv
+
+      - name: Export
+        run: just export
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v3
+        with:
+          name: ${{ env.game_name }}-v${{ env.game_version }}
+          path: dist/*
+          retention-days: 1
+
+  publish:
+    runs-on: ubuntu-22.04
+    timeout-minutes: 30
+    needs: [build]
+
+    if: startsWith(github.ref, 'refs/tags/')
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: extractions/setup-just@v1
+
+      - name: Load dotenv
+        run: just ci-load-dotenv
+
+      - name: Download artifact
+        uses: dawidd6/action-download-artifact@v2
+        with:
+          workflow: ${{ github.event.workflow_run.workflow_id }}
+          name: ${{ env.game_name }}-v${{ env.game_version }}
+          path: dist/
+          skip_unpack: false
+
+      - name: Publish
+        run: just publish
+        env:
+          BUTLER_API_KEY: ${{ secrets.BUTLER_API_KEY }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      # # Installing rsync is needed in order to deploy to GitHub Pages. Without it, the build will fail.
+      # - name: Install rsync
+      #   run: |
+      #     apt-get update && apt-get install -y rsync
+      #
+      # - name: Deploy to GitHub Pages
+      #   uses: JamesIves/github-pages-deploy-action@v4
+      #   with:
+      #     token: ${{ secrets.GITHUB_TOKEN }}
+      #     branch: gh-pages
+      #     folder: build/web