Fix mishandling of URL

[gwynne]

These changes are now available in 2.12.3

We have for some time now been incorrectly encoding URLs in an incorrect format that fails to trivially round-trip back through decoding. This is now fixed. Any previously broken data stored in a database affected by this issue will now be correctly read back and will have the correct format when next written.

Note

This is not related in any way to the recent issues with Vapor's URI type; it is a separate concern affecting the URL type that comes from Foundation.

Also incidentally fixes #255

[codecov-commenter]

Codecov Report

Attention: 2 lines in your changes are missing coverage. Please review.

Comparison is base (81d1106) 36.27% compared to head (ccba064) 37.86%.
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #257      +/-   ##
==========================================
+ Coverage   36.27%   37.86%   +1.58%     
==========================================
  Files          13       13              
  Lines         736      750      +14     
==========================================
+ Hits          267      284      +17     
+ Misses        469      466       -3     

Files	Coverage Δ
Sources/PostgresKit/ConnectionPool+Postgres.swift	35.71% <ø> (ø)
Sources/PostgresKit/PostgresDataTranslation.swift	67.28% <100.00%> (+3.73%)	⬆️
Sources/PostgresKit/PostgresDatabase+SQL.swift	85.29% <100.00%> (ø)
Sources/PostgresKit/SQLPostgresConfiguration.swift	85.10% <100.00%> (ø)
...stgresConnectionSource+PostgresConfiguration.swift	0.00% <0.00%> (ø)
...PostgresKit/Deprecations/PostgresDataEncoder.swift	0.00% <0.00%> (ø)