fix: camelcase and pascalcase transformation logic

[42atomys]

Description

In sprig, camelCase return a PascalCase and don't respect the separation logic between both functions.

Changes

• Introduce a toPascalCase function to transform a string to a PascalCase
• Fix the behivour of toCamelCase function to transform a string to a camelCase

Fixes Masterminds#328

Checklist

• I have read the CONTRIBUTING.md document.
• My code follows the code style of this project.
• I have added tests to cover my changes.
• All new and existing tests passed.
• I have updated the documentation accordingly.
• This change requires a change to the documentation on the website.

Additional Information

This edit are related to Masterminds#328

Backport ticket from @ghostsquad

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Files	Coverage Δ
strings_functions.go	100.0% <100.0%> (ø)