Make DataRow Sendable

[fabianfett]

Motivation

For Swift 5.6, we want to support Sendable checks. DataRow generates a lot of warnings in CI today.

Changes

• Make DataRow Sendable

[codecov-commenter]

Codecov Report

Merging #250 (efd07c2) into main (1cd8d36) will increase coverage by 3.96%.
The diff coverage is n/a.

❗ Current head efd07c2 differs from pull request most recent head 80acc05. Consider uploading reports for the commit 80acc05 to get more accurate results

@@            Coverage Diff             @@
##             main     #250      +/-   ##
==========================================
+ Coverage   39.78%   43.75%   +3.96%     
==========================================
  Files         115      115              
  Lines        9513     9512       -1     
==========================================
+ Hits         3785     4162     +377     
+ Misses       5728     5350     -378     

Flag	Coverage Δ
unittests	43.75% <ø> (+3.96%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
Sources/PostgresNIO/New/Messages/DataRow.swift	95.38% <ø> (+4.61%)	⬆️
...ces/PostgresNIO/New/Data/Int+PostgresCodable.swift	30.71% <0.00%> (-1.31%)	⬇️
...es/PostgresNIO/Connection/PostgresConnection.swift	15.42% <0.00%> (-1.13%)	⬇️
Sources/PostgresNIO/New/PostgresQuery.swift	86.66% <0.00%> (ø)
Sources/PostgresNIO/New/PostgresCodable.swift	91.66% <0.00%> (ø)
...es/PostgresNIO/New/Data/Date+PostgresCodable.swift	89.28% <0.00%> (ø)
...es/PostgresNIO/New/Data/JSON+PostgresCodable.swift	100.00% <0.00%> (ø)
...es/PostgresNIO/New/Data/UUID+PostgresCodable.swift	98.30% <0.00%> (ø)
...s/PostgresNIO/New/Extensions/ByteBuffer+PSQL.swift	100.00% <0.00%> (ø)
.../PostgresNIO/New/Data/String+PostgresCodable.swift	100.00% <0.00%> (ø)
... and 31 more

[gwynne]

Why 5.6 rather than 5.5?

[gwynne]

Marching onward!