Added cast date32 -> i64 and date64 -> i32

[ritchie46]

This add casting the primitive values of datetypes, date32, date64 to integers.

[codecov]

Codecov Report

Merging #308 (524ea7f) into main (2873e1a) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #308      +/-   ##
==========================================
+ Coverage   80.57%   80.59%   +0.01%     
==========================================
  Files         324      324              
  Lines       21221    21231      +10     
==========================================
+ Hits        17099    17111      +12     
+ Misses       4122     4120       -2     

Impacted Files	Coverage Δ
src/compute/cast/mod.rs	89.31% <100.00%> (+0.08%)	⬆️
tests/it/compute/cast.rs	99.32% <100.00%> (+0.01%)	⬆️
src/io/json/read/reader.rs	75.67% <0.00%> (+1.35%)	⬆️
src/io/json_integration/write.rs	6.25% <0.00%> (+6.25%)	⬆️

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