Attempt to fix the phar build process

Author: floriankraemer

.github/workflows/phar-build.yaml

@@ -25,7 +25,9 @@ jobs:
       run: composer install --no-dev --optimize-autoloader
 
     - name: Inject version from tag
-      run: sed -i "s/public const VERSION = .*/public const VERSION = '${{ github.ref_name }}';/" src/Application.php
+      run: |
+        VERSION=$(echo "${{ github.ref_name }}" | sed 's/^\\//')
+        sed -i "s/public const VERSION = .*/public const VERSION = '$VERSION';/" src/Application.php
 
     - name: Build PHAR
       run: composer build-phar