Fix call to logger warn method.

[AdamBark]

warn is not a method, warning appears to be correct.

Q	A
Bug fix? (use the a.b branch)	[yes ]
New feature/enhancement? (use the a.x branch)	[ no]
Deprecations?	[ None]
BC breaks? (use the c.x branch)	[ None?]
Automated tests included?	[ not applicable]

Description:

When running bin/console mautic:iplookup:download the following error is thrown without this bugfix if you have no credentials for the Maxmind service.

                                                                                                
  [Symfony\Component\ErrorHandler\Error\UndefinedMethodError]                                   
  Attempted to call an undefined method named "warn" of class "Symfony\Bridge\Monolog\Logger".  
  Did you mean to call "warning"?

Steps to test this PR:

1. Open this PR on Gitpod or pull down for testing locally (see docs on testing PRs here)
2. Run php bin/console mautic:iplookup:download

[kuzmany]

Code looks good 🫰

[mollux]

@AdamBark while your change fixes that specific error on that specific place, there are 3 other occurrences around that code that use the same non-existing method.
Can you please address those too?

[codecov]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (bee6b30) 58.60% compared to head (45ec17c) 58.60%.
Report is 4 commits behind head on 5.0.

Additional details and impacted files

@@             Coverage Diff              @@
##                5.0   #13252      +/-   ##
============================================
- Coverage     58.60%   58.60%   -0.01%     
  Complexity    32985    32985              
============================================
  Files          2183     2183              
  Lines         98756    98756              
============================================
- Hits          57877    57876       -1     
- Misses        40879    40880       +1     

Files	Coverage Δ
...ndles/CoreBundle/IpLookup/IP2LocationAPILookup.php	0.00% <0.00%> (ø)
...dles/CoreBundle/IpLookup/MaxmindDownloadLookup.php	21.21% <0.00%> (ø)
...ndles/CoreBundle/IpLookup/IP2LocationBinLookup.php	0.00% <0.00%> (ø)

... and 1 file with indirect coverage changes

[kuzmany]

Good 👍

[mollux]

Thanks for the additional changes!

[mollux]

@AdamBark I just noticed you made the PR against 5.x, and it should be 5.0, as it's a bugfix.

Can you rebase your changes based on 5.0? then this PR can be merged

[AdamBark]

@AdamBark I just noticed you made the PR against 5.x, and it should be 5.0, as it's a bugfix.

Can you rebase your changes based on 5.0? then this PR can be merged

Will do. I was a bit confused by the various documentations on which branch it should be on so thanks for the clarification. Perhaps this line "All PRs are made against the c.x branch in the first instance (e.g. 5.x)" should be amended?