Add new protocol PostgresNonThrowingEncodable

[fabianfett]

Motivation

Currently creating a PostgresQuery through String interpolation always throws. The reason to support throwing in PostgresEncodable is, that the Encodable protocol enforces throwing (and we do want to support JSON). But for most of the primary types throwing is totally useless.

Changes

• We introduce the protocol PostgresNonThrowingEncodable, which inherits from PostgresEncodable but enforces that the encode method does not throw
• We add a separate entry points for PostgresNonThrowingEncodable in PostgresQuery and PostgresBinding to reduce the number of places where we throw

Result

• way less throwing in places where we don't actually throw

[codecov-commenter]

Codecov Report

Merging #322 (a9b1f1f) into main (b5cca72) will decrease coverage by 0.08%.
The diff coverage is 94.91%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #322      +/-   ##
==========================================
- Coverage   41.62%   41.54%   -0.09%     
==========================================
  Files         115      115              
  Lines        9377     9436      +59     
==========================================
+ Hits         3903     3920      +17     
- Misses       5474     5516      +42     

Flag	Coverage Δ
unittests	41.54% <94.91%> (-0.09%)	⬇️

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

Impacted Files	Coverage Δ
...es/PostgresNIO/New/Data/Bool+PostgresCodable.swift	95.34% <ø> (ø)
...s/PostgresNIO/New/Data/Bytes+PostgresCodable.swift	64.70% <ø> (ø)
...es/PostgresNIO/New/Data/Date+PostgresCodable.swift	89.28% <ø> (ø)
...s/PostgresNIO/New/Data/Float+PostgresCodable.swift	76.66% <ø> (ø)
...ces/PostgresNIO/New/Data/Int+PostgresCodable.swift	36.60% <ø> (ø)
.../PostgresNIO/New/Data/String+PostgresCodable.swift	100.00% <ø> (ø)
...es/PostgresNIO/New/Data/UUID+PostgresCodable.swift	96.96% <ø> (ø)
...s/PostgresNIO/New/Data/Array+PostgresCodable.swift	70.94% <89.28%> (-22.32%)	⬇️
Sources/PostgresNIO/New/PostgresCodable.swift	93.87% <100.00%> (+2.21%)	⬆️
Sources/PostgresNIO/New/PostgresQuery.swift	75.00% <100.00%> (-12.18%)	⬇️
... and 2 more

[gwynne]

*mutter mutter grumble*