Fix build break in Swift 5, current fix also support previous version…

[rickyzh]

… of swift

New Pull Request Checklist

• I have read and understood the CONTRIBUTING guide

• 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 master to avoid conflicts (via merge from master or rebase)

• I have added the required tests to prove the fix/feature I am adding

• I have updated the documentation (if necessary)

• I have run the tests and they pass

• I have run the lint and it passes (pod lib lint)

This merge request fixes / refers to the following issues: ...

Pull Request Description

Fix build break in Swift 5, current fix also support previous versions, 90th lines in CocoaLumberjack.swift

[OSSPolice]

	2 Warnings
⚠️	Any changes to library code should be reflected in the CHANGELOG. Please consider adding a note there about your change.
⚠️	The library files were changed, but the tests remained unmodified. Consider updating or adding to the tests to match the library changes.

Generated by 🚫 Danger

[codecov-io]

Codecov Report

Merging #1044 into master will increase coverage by 0.53%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1044      +/-   ##
==========================================
+ Coverage   36.82%   37.35%   +0.53%     
==========================================
  Files          27       27              
  Lines        3927     3927              
==========================================
+ Hits         1446     1467      +21     
+ Misses       2481     2460      -21

Impacted Files	Coverage Δ
Classes/DDASLLogger.m	55.76% <0%> (+1.92%)	⬆️
Classes/DDOSLogger.m	74.28% <0%> (+57.14%)	⬆️

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