Add support for time zones in DateTag.

[fpseverino]

These changes are now available in 1.11.0

Adds an additional parameter to DateTag that takes a time zone ID and uses it to set the timeZone property of the DateFormatter.

For example (as you can see in the added tests):

The date is #date(now, "yyyy-MM-dd'T'HH:mm", "America/New_York")

will be three hours ahead of:

The date is #date(now, "yyyy-MM-dd'T'HH:mm", "America/Los_Angeles")

[codecov]

Codecov Report

Attention: Patch coverage is 71.42857% with 2 lines in your changes missing coverage. Please review.

Project coverage is 81.64%. Comparing base (f6a08a1) to head (fff9bec).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #131      +/-   ##
==========================================
- Coverage   82.09%   81.64%   -0.46%     
==========================================
  Files          25       25              
  Lines        2603     2517      -86     
==========================================
- Hits         2137     2055      -82     
+ Misses        466      462       -4     

Files	Coverage Δ
Sources/LeafKit/LeafSyntax/LeafTag.swift	77.04% <71.42%> (-1.53%)	⬇️

... and 17 files with indirect coverage changes

[0xTim]

Thanks!