Fix set-cookie parsing

[Vovcharaa]

New Pull Request Checklist

• I have read the Documentation
• I have searched for a similar pull request in the project and found none
• I have updated this branch with the latest main branch to avoid conflicts (via merge from master or rebase)
• I have added the required tests to prove the fix/feature I'm adding
• I have updated the documentation (if necessary)
• I have run the tests without failures

Additional context and info (if any)

Fix #1674

[Vovcharaa]

RegEx taken here: dart-lang/http#362 (comment)

[AlexV525]

Please add tests.

[Vovcharaa]

Please add tests.

I have no experience with dart tests, so I am not sure if I can do this, but I will look into it.

[AlexV525]

I have no experience with dart tests, so I am not sure if I can do this, but I will look into it.

This is easy by expecting a multi-value cookie to be parsed as multi values. An example:

dio/dio/test/basic_test.dart

Lines 12 to 20 in 62622e2

	final headers = Headers.fromMap({
	'set-cookie': ['k=v', 'k1=v1'],
	'content-length': ['200'],
	'test': ['1', '2'],
	});
	headers.add('SET-COOKIE', 'k2=v2');
	expect(headers.value('content-length'), '200');
	expect(Future(() => headers.value('test')), throwsException);
	expect(headers['set-cookie']?.length, 3);

[Vovcharaa]

@AlexV525 done

[AlexV525]

Sorry, please update the CHANGELOG too.

[Vovcharaa]

@AlexV525 done