[IAC-547] Remove strftime from stdlib as it has already been replaced by the puppet agent since 4.8.0

[carabasdaniel]

Removing strftime as it was already superseded by https://github.com/puppetlabs/puppet/blob/master/lib/puppet/functions/strftime.rb

[codecov-io]

Codecov Report

Merging #1097 into master will increase coverage by 0.96%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master   #1097      +/-   ##
=========================================
+ Coverage    3.74%   4.71%   +0.96%     
=========================================
  Files         186     185       -1     
  Lines        5338    5258      -80     
=========================================
+ Hits          200     248      +48     
+ Misses       5138    5010     -128

Impacted Files	Coverage Δ
lib/puppet/type/file_line.rb	96.36% <0%> (+1.81%)	⬆️
lib/puppet/provider/file_line/ruby.rb	62.62% <0%> (+47.47%)	⬆️

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[michaeltlombardi]

Marking this as a maintenance commit as the function is already overridden by the function within Puppet, meaning this is not a backwards breaking change.

[DavidS]

Relabelled and retitled as bugfix so it shows up on the changelog.