Try explicitly adding composer

Author: TRowbotham

.github/workflows/tests.yml

@@ -53,6 +53,7 @@ jobs:
           extensions: mbstring, opcache, pcre, gmp
           ini-values: zend.assertions=1, opcache.enable_cli=1, opcache.memory_consumption=256, opcache.jit=${{ matrix.php-jit == 'on' && 1255 || 'disable' }}, opcache.jit_buffer_size=${{ matrix.php-jit == 'on' && '256M' || '0' }}
           coverage: none
+          tools: composer:v2
         env:
           fail-fast: true
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}