Rebuilt to address dotnet/core#3388 - 5.0.0 package didn't have proper dates on assemblies, causing some date-related operations on assemblies to fail.

• Removed netstandard1.1 support.
• Added AutofacChildScopeServiceProviderFactory to address ASP.NET Core 3.0 / .NET Core generic hosting when using a child lifetime scope as the "root" of the app.
• Added AutofacServiceProvider.LifetimeScope property to allow retrieving the root container / scope from the provider.
• Added IServiceProvider.GetAutofacRoot() extension method for more conveniently and safely accessing the AutofacServiceProvider.LifetimeScope property.

• Removed netstandard1.1 support.
• Added AutofacChildScopeServiceProviderFactory to address ASP.NET Core 3.0 / .NET Core generic hosting when using a child lifetime scope as the "root" of the app.
• Added AutofacServiceProvider.LifetimeScope property to allow retrieving the root container / scope from the provider.
• Added IServiceProvider.GetAutofacRoot() extension method for more conveniently and safely accessing the AutofacServiceProvider.LifetimeScope property.

• Reduced package dependencies when using .NET Standard 2.0
• Prevent Disposer stack space leak when IServiceProvider is looked up

Resolved #32: Updated minimum Autofac version to 4.6.1 to ensure an IServiceProvider built on a child lifetime scope can properly resolve things like IOptions<T>.

• Enabled SourceLink support.
• Added netstandard2.0 target.
• Resolved #30: Implemented IDisposable on AutofacServiceProvider to better handle application shutdown and conform to IDisposable specification test.

Resolved #29: Updated minimum core Autofac version to 4.2.0 to avoid conflicts involving SerializableAttribute at runtime.

• Resolved #25: Updated tooling, references to remove NETStandard.Library conflict.
• Increased minimum Autofac core version to 4.0.1 to improve the full .NET Framework experience.

Added support for specifying a child lifetime scope tag to serve as the service provider "root" - an advanced option that allows you more control over isolating things registered using the Microsoft.Extensions.DependencyInjection interfaces.

• Added IServiceProviderFactory implementation (AutofacServiceProviderFactory).
• AddAutofac extension method on ServiceCollection for adding IServiceProviderFactory.
• Microsoft.Extensions.DependencyInjection.Abstractions dependency upgraded to 1.1.0.
• Release notes link to NuGet package.