Update str_to_bool function to include 'nope' as a valid false value

[tkosman]

Let’s keep things fair.
If we're parsing 'yup' and 'yep' as bool type True.
Definitely 'nope' belongs to bool type False.

Example:

import os
import sanic

os.environ["SANIC_NOPE"] = "nope"

app = sanic.Sanic("Nope")

@app.route("/")
async def nope(request):
    return sanic.response.json({"NOPE IS": app.config.get("NOPE")}) # {NOPE IS: false}


if __name__ == "__main__":
    app.run()

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 87.643%. Comparing base (f240432) to head (4673835).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main     #3080   +/-   ##
=========================================
  Coverage   87.643%   87.643%           
=========================================
  Files          103       103           
  Lines         7729      7729           
  Branches      1225      1225           
=========================================
  Hits          6774      6774           
  Misses         660       660           
  Partials       295       295           

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