Fix build

Author: tvdijen

.github/workflows/php.yml

@@ -147,9 +147,10 @@ jobs:
         run: echo COMPOSER_CACHE="$(composer config cache-files-dir)" >> "$env:GITHUB_ENV"
 
       - name: Get COMPOSER_ROOT_VERSION from composer.json branch alias
+        shell: bash
         run: |
             echo ROOT_VERSION="$(composer config extra.branch-alias.dev-master)" >> "$env:GITHUB_ENV"
-            if [ -z "$ROOT_VERSION" ]; then
+            if [ -z "{{ $env.ROOT_VERSION }}" ]; then
               echo "Could not read extra.branch-alias.dev-master from composer.json" >&2
               exit 1
             fi