fix: handle empty value for select property

[iamalexchip]

If the a select property is empty the

Notion\Pages\Properties\Option::fromArray(): Argument #1 ($array) must be of type array, null given, called in /vendor/mariosimao/notion-sdk-php/src/Pages/Properties/Select.php on line 49

[codecov-commenter]

Codecov Report

Merging #86 (5876d50) into main (6d79e97) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##               main      #86   +/-   ##
=========================================
  Coverage     98.84%   98.84%           
  Complexity     1122     1122           
=========================================
  Files           101      101           
  Lines          3632     3632           
=========================================
  Hits           3590     3590           
  Misses           42       42           

Impacted Files	Coverage Δ
src/Pages/Properties/Option.php	100.00% <100.00%> (ø)
src/Pages/Properties/Select.php	100.00% <100.00%> (ø)

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[mariosimao]

@iamalexchip thanks for your contribution!

Changes are now available on version 0.5.2.