feat(eslint-plugin): [typedef] add variable-declaration-ignore-function

[a-tarasyuk]

Fixes #1555

[typescript-eslint]

Thanks for the PR, @a-tarasyuk!

typescript-eslint is a 100% community driven project, and we are incredibly grateful that you are contributing to that community.

The core maintainers work on this in their personal time, so please understand that it may not be possible for them to review your work immediately.

Thanks again!

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[codecov]

Codecov Report

Merging #1578 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #1578      +/-   ##
==========================================
+ Coverage   95.53%   95.53%   +<.01%     
==========================================
  Files         142      142              
  Lines        6626     6628       +2     
  Branches     1897     1898       +1     
==========================================
+ Hits         6330     6332       +2     
  Misses        106      106              
  Partials      190      190

Impacted Files	Coverage Δ
...plugin/src/rules/explicit-module-boundary-types.ts	86.2% <100%> (+0.49%)	⬆️

[bradzacher]

LGTM - thanks for doing this!