Bump hed-validator dependency to v3.13.4

[happy5214]

See the release notes at https://github.com/hed-standard/hed-javascript/releases/tag/v3.13.4. The main feature in this release is validating TSV files in a way that respects their onset column (merging rows with the same onset into a single event and sorting events by onset).

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 85.46%. Comparing base (39baeb8) to head (9f2d139).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1913      +/-   ##
==========================================
+ Coverage   83.57%   85.46%   +1.89%     
==========================================
  Files          92      131      +39     
  Lines        3890     6262    +2372     
  Branches     1271     1544     +273     
==========================================
+ Hits         3251     5352    +2101     
- Misses        541      806     +265     
- Partials       98      104       +6     

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[happy5214]

@rwblair Please merge this. Several real-world datasets are currently failing validation because of issues fixed in this release.