feat: New method `addYear`

[flaviendelangle]

Needed for #5504

[codecov-commenter]

Codecov Report

Merging #623 (6b755a9) into master (77f89b4) will not change coverage. The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master      #623   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           16        16           
  Lines         1482      1498   +16     
  Branches       191       190    -1     
=========================================
+ Hits          1482      1498   +16     

Impacted Files	Coverage Δ
...kages/date-fns-jalali/src/date-fns-jalali-utils.ts	100.00% <100.00%> (ø)
packages/date-fns/src/date-fns-utils.ts	100.00% <100.00%> (ø)
packages/dayjs/src/dayjs-utils.ts	100.00% <100.00%> (ø)
packages/js-joda/src/js-joda-utils.ts	100.00% <100.00%> (ø)
packages/luxon/src/luxon-utils.ts	100.00% <100.00%> (ø)
packages/moment/src/moment-utils.ts	100.00% <100.00%> (ø)

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