fix: test phpunit-32bits on ubuntu-slim

Signed-off-by: Josh <josh.t.richards@gmail.com>

Author: joshtrichards

.github/workflows/phpunit-32bits.yml

@@ -22,7 +22,7 @@ concurrency:
 
 jobs:
   phpunit-32bits:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-slim
 
     if: ${{ github.repository_owner != 'nextcloud-gmbh' }}