feat(isLicensePlate): fi-FI locale support

[Marcholio]

Added support for Finnish license plate validation. Valid examples from traficom site:

• TRA-100, JCK-33 - normal car
• QUU-1 - special plate available on special request
• 10-TRF, BX-971 - motorcycle
• MA-126 - museum car
• 100-EAI - tractor or other work equipment
• 199-AA - Snowmobile
• C-11012, CD-1124 - Diplomat car

Basically all options can be written with dash, with space or all together.

Checklist

• PR contains only changes related; no stray files, etc.
• README updated (where applicable)
• Tests written (where applicable)

[codecov]

Codecov Report

Merging #1790 (c4ac9a6) into master (13651ea) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master     #1790   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          102       102           
  Lines         2029      2030    +1     
  Branches       457       457           
=========================================
+ Hits          2029      2030    +1     

Impacted Files	Coverage Δ
src/lib/isLicensePlate.js	100.00% <100.00%> (ø)

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[tux-tn]

LGTM 🎉 ! Thank you for your PR @Marcholio

[profnandaa]

thanks for your contrib! 🎉