wip: clamp version 6 of composer for old php

Greg Bowler · Greg Bowler · commit 00320fd6bd7b · 2023-09-18T13:12:15.000+01:00
diff --git a/.github/workflows/ci-php73.yml b/.github/workflows/ci-php73.yml
@@ -19,4 +19,5 @@ jobs:
           bootstrap: vendor/autoload.php
           configuration: test/phpunit.xml
           args: --coverage-text
+          version: 6
           php_version: "7.3"
