parallel: false doesn't work

[kuznetsss]

Hi, thanks for the action!

It seems parallel: false option doesn't work, even if it is provided, tests are still executed in parallel.

I created a simple repository to reproduce the issue: https://github.com/kuznetsss/k6_parallel_test.

The code looks the same for both branches in

run-k6-action/src/index.ts

Lines 90 to 148 in a784f35

	if (parallel) {
	const childProcesses = [] as any[];
	commands.forEach(command => {
	const child = runCommand(command);
	childProcesses.push(child);
	TEST_PIDS.push(child.pid);
	allPromises.push(new Promise(resolve => {
	child.on('exit', (code: number, signal: string) => {
	const index = TEST_PIDS.indexOf(child.pid);
	if (index > -1) {
	TEST_PIDS.splice(index, 1);
	}
	if (code !== 0) {
	if (failFast) {
	console.log('🚨 Fail fast enabled. Stopping further tests.');
	childProcesses.forEach(child => {
	if (!child.killed) {
	child.kill('SIGINT');
	}
	});
	process.exit(1); // Exit parent process with failure status
	} else {
	console.log(`🚨 Test failed with code: ${code} and signal: ${signal}`);
	allTestsPassed = false;
	}
	} else {
	console.log('✅ Test passed');
	}
	resolve();
	});
	}));
	});
	} else {
	for (const command of commands) {
	const child = runCommand(command);
	TEST_PIDS.push(child.pid);
	allPromises.push(new Promise<void>(resolve => {
	child.on('exit', (code: number, signal: string) => {
	const index = TEST_PIDS.indexOf(child.pid);
	if (index > -1) {
	TEST_PIDS.splice(index, 1);
	}
	if (code !== 0) {
	if (failFast) {
	console.log('🚨 Fail fast enabled. Stopping further tests.');
	process.exit(1); // Exit parent process with failure status
	} else {
	console.log(`🚨 Test failed with code: ${code} and signal: ${signal}`);
	allTestsPassed = false;
	}
	} else {
	console.log('✅ Test passed');
	}
	resolve();
	});
	}));
	}
	}