Added lower

[Xuanwo]

Signed-off-by: Xuanwo github@xuanwo.io

Part of #635

[codecov]

Codecov Report

Merging #641 (6eba31a) into main (b853d95) will increase coverage by 0.02%.
The diff coverage is 100.00%.

❗ Current head 6eba31a differs from pull request most recent head fa9693b. Consider uploading reports for the commit fa9693b to get more accurate results

@@            Coverage Diff             @@
##             main     #641      +/-   ##
==========================================
+ Coverage   69.91%   69.94%   +0.02%     
==========================================
  Files         299      300       +1     
  Lines       16628    16644      +16     
==========================================
+ Hits        11625    11641      +16     
  Misses       5003     5003              

Impacted Files	Coverage Δ
src/compute/lower.rs	100.00% <100.00%> (ø)
src/datatypes/schema.rs	37.93% <0.00%> (ø)

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[jorgecarleitao]

Thanks a lot! Left some comments

[ghuls]

Shouldn't the test include some real UTF8 characters instead of only the ASCII subset?
Like some of the characters listed here: https://www.ibm.com/docs/en/i/7.2?topic=tables-unicode-lowercase-uppercase-conversion-mapping-table

[Xuanwo]

Shouldn't the test include some real UTF8 characters instead of only the ASCII subset?

Addressed, thanks for advice.

[jorgecarleitao]

Thanks a lot, really well tested! 💯