better date updating from arxiv after publication

[GlazerMann]

Existing code did not check for "date" values

[codecov]

Codecov Report

Merging #749 into master will decrease coverage by 1.55%.
The diff coverage is 100%.

@@             Coverage Diff             @@
##             master    #749      +/-   ##
===========================================
- Coverage     69.35%   67.8%   -1.56%     
  Complexity     1621    1621              
===========================================
  Files            12      12              
  Lines          3270    3274       +4     
===========================================
- Hits           2268    2220      -48     
- Misses         1002    1054      +52

Impacted Files	Coverage Δ	Complexity Δ
apiFunctions.php	68.39% <100%> (+0.34%)	0 <0> (ø)	⬇️
Template.php	73.52% <0%> (-2.57%)	1450% <0%> (ø)
expandFns.php	90.71% <0%> (+0.71%)	0% <0%> (ø)	⬇️

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