Add Saint Lucia holidays

[Prateekshit73]

Proposed change

Added Saint Lucia holidays
Closes #1262

Type of change

• New country/market holidays support (thank you!)
• Supported country/market holidays update (calendar discrepancy fix, localization)
• Existing code/documentation/test/process quality improvement (best practice, cleanup, refactoring, optimization)
• Dependency update (version deprecation/pin/upgrade)
• Bugfix (non-breaking change which fixes an issue)
• Breaking change (a code change causing existing functionality to break)
• New feature (new holidays functionality in general)

Checklist

• I've followed the contributing guidelines
• I've successfully run make check, all checks and tests are green

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (915dafb) to head (b23a6ed).
Report is 5 commits behind head on dev.

Additional details and impacted files

@@            Coverage Diff            @@
##               dev     #2266   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          199       200    +1     
  Lines        12144     12177   +33     
  Branches      1731      1731           
=========================================
+ Hits         12144     12177   +33     

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[KJhellico]

According to Bank Holidays Act

If any of the above days fall on a Sunday, or bank holiday, the Monday, or other day, immediately next following not being a holiday is a bank holiday, unless some other day is appointed for the purpose.

@Prateekshit73, you can apply observed holidays support for LC. The rules will be similar, for example, to Saint Kitts and Nevis.

[PPsyrius]

Looks pretty good, just a few typoes here:

[PPsyrius]

Here are the remaining test case changes as previously requested by @KJhellico as well as a missing one for Emancipation Day:

    def test_emancipation_day(self):
        name = "Emancipation Day"
        self.assertHolidayName(name, (f"{year}-08-01" for year in range(1979, 2050)))
        dt = (
            "2004-08-02",
            "2010-08-02",
            "2021-08-02",
        )
        self.assertHolidayName(f"{name} (observed)", dt)
        self.assertNoNonObservedHoliday(dt)

Aside from that, this PR looks more or less ready for merging to me 👍

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[PPsyrius]

LGTM 🇱🇨

[KJhellico]

LGTM!

[arkid15r]

Another country! We're getting closer to 160 target.
Thank you @Prateekshit73 and @KJhellico @PPsyrius for reviewing

🇱🇨 LGTM