Update GitHub release checklist

[rly]

• Add a step to manually run all tests before merging
• Minor updates to other steps
• Make consistent with HDMF release checklist

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.96%. Comparing base (1c313b4) to head (60c8a85).

Additional details and impacted files

@@           Coverage Diff           @@
##              dev    #1872   +/-   ##
=======================================
  Coverage   91.96%   91.96%           
=======================================
  Files          27       27           
  Lines        2663     2663           
  Branches      686      686           
=======================================
  Hits         2449     2449           
  Misses        142      142           
  Partials       72       72           

Flag	Coverage Δ
integration	72.36% <ø> (ø)
unit	84.07% <ø> (ø)

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