fix: restore checkReqs in prepare.js

[erisu]

Motivation and Context

Restore checkReqs in prepare.js

Description

In PR #1431, additional usage of checkReqs was added to prepare.js.
In PR #1154, the only usage of checkReqs was removed so the requirement was deleted.

Because of #1154 was merged first and #1431 was merged second, with no conflict, the test ended up failing on master.

This PR just adds back the require statement.

Testing

npm t

Checklist

• I've run the tests to see all new and existing tests pass
• I added automated test coverage as appropriate for this change
• Commit is prefixed with (platform) if this change only applies to one platform (e.g. (android))
• If this Pull Request resolves an issue, I linked to the issue in the text above (and used the correct keyword to close issues using keywords)
• I've updated the documentation if necessary

[codecov-commenter]

Codecov Report

Merging #1434 (83b1163) into master (bd0c8ce) will increase coverage by 3.01%.
The diff coverage is 87.50%.

@@            Coverage Diff             @@
##           master    #1434      +/-   ##
==========================================
+ Coverage   72.95%   75.96%   +3.01%     
==========================================
  Files          21       21              
  Lines        1653     1677      +24     
==========================================
+ Hits         1206     1274      +68     
+ Misses        447      403      -44     

Impacted Files	Coverage Δ
lib/check_reqs.js	71.05% <76.47%> (+0.68%)	⬆️
lib/create.js	94.32% <100.00%> (+0.08%)	⬆️
lib/prepare.js	60.00% <100.00%> (+15.38%)	⬆️

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