Fluent-validation

Add ASP.NET Core-compatible version of the email address validator.
Simplify the advanced testhelper syntax.
Add support for ASP.NET Core 3.
Add support for defining child rules inline.
ValidatorDescriptor now has consistent handling of model-level rules.
RuleForEach can now access collection index in error message with {CollectionIndex} placeholder.
Welsh language translations of default error messages.
Hungrian language translations of default error messages.
Indonesian language translations of default error messages.
Using RuleForEach combined with When is now more intuitive.
Fixed order of rule execution when using async validation.

Added simplified version of several messages across all translations to aid with ASP.NET Clientside validation.
New enum validator for string properties.

Fix issue in ASP.NET Core integration with GetServiceProvider not working correctly when invoked against a CustomContext/MessageBuilderContext.
Improved how LanguageStringSource works with error-code overrides.
Fix thread-safety issue with use of PropertyValidatorOptions.Empty (now removed).
Improved how calls to When/Unless are handled internally.
DelegatingValidator is now marked as deprecated.
Improvements to Croatian language translations.
Improvements to Georgian language translations.
Resolved subtle bug where top-level WhenAsync wouldn't work correctly when wrapping a top-level call to When.

Fix issue with WebApi integration where DataAnnotations validation could generate duplicate messages when used in the same
project as FluentValidation.

Fix typo in FluentValidation.DependencyInjectionExtensions package name.

Resolved issue using InjectValidator with RuleForEach.
Add support for a default IValidatorInterceptor to be registered with the ASP.NET Core Service Provider.
Added "Without" test extensions for consistency with existing "With" text extensions.