Fix #218: Respect composer lock

[Oscaner]

Respect composer lock, no update any packages during package install.

[mcaskill]

This condition was brought up during the refactor to support Composer 2 and bounced around a bit ^[1] [2].

[mcaskill]

Inconsistent indentation:

Suggested change

	if ($this->state->forceUpdate()) {
	// Force update mode so that new packages are processed rather
	// than just telling the user that composer.json and
	// composer.lock don't match.
	$installer->setUpdate(true);
	} else {
	$this->logger->log('You may need to manually run composer update to apply merge settings');
	}
	if ($this->state->forceUpdate()) {
	// Force update mode so that new packages are processed rather
	// than just telling the user that composer.json and
	// composer.lock don't match.
	$installer->setUpdate(true);
	} else {
	$this->logger->log('You may need to manually run composer update to apply merge settings');
	}

[reedy]

This still needs fixing at least...

[raileanunalexandru]

We have tested this in quite a few scenarios and it's correctly respecting the intended functionality.
Can we have this released via a new tag so we can properly make use of it?
Patching this via composer doesn't work, so at the moment we have to reference this commit instead of the regular tag.

Maybe @reedy if you could have a look please?

[reedy]

This still needs fixing at least...

[raileanunalexandru]

Hi @reedy thank you for your activity on this.
Since this seems to have been forgotten by the initiator, i have made a new pull request to address this by fixing the indentation giving credit to the author.
Could we maybe close this pull request the have a look into the new one here?
#232

Thank you!