Do not introduce breaking changes in minor versions

[janousek]

Issue Summary

Version 9.15.0 contains undocumented breaking changes in SendGridCient. Now it is impossible to pass own configuration using SendGridClientOptions. Because of this it is impossible to set some of options avaiable in SendGridClientOptions (for example ReliabilitySettings).

And now I discovered that ReliabilitySettings is totaly ignored (it is hardcoded):

sendgrid-csharp/src/SendGrid/BaseClient.cs

Line 226 in cf61849

return new HttpClient(new RetryDelegatingHandler(new ReliabilitySettings()));

sendgrid-csharp/src/SendGrid/BaseClient.cs

Line 245 in cf61849

var retryHandler = new RetryDelegatingHandler(httpClientHandler, new ReliabilitySettings());

This is shame. Your developers should really think about changes that they make (merget to master branch) before you publish new version. You are breaking existing code.

[childish-sambino]

So this is the old line:

sendgrid-csharp/src/SendGrid/SendGridClient.cs

Line 275 in 908074c

return new HttpClient(new RetryDelegatingHandler(DefaultOptions.ReliabilitySettings));

It uses DefaultOptions which was defined here:

sendgrid-csharp/src/SendGrid/SendGridClient.cs

Line 39 in 908074c

private static readonly SendGridClientOptions DefaultOptions = new SendGridClientOptions();

How were you able to modify the ReliabilitySettings of DefaultOptions? I don't see any accessors for DefaultOptions or its ReliabilitySettings (when looking at the code before the changes in question).

[janousek]

ReliabilitySettings gets broken in this commit:
d6c2349

[childish-sambino]

Ahhh, perfect. Thanks! So it's been broken since 9.11.0 and now I understand why it was the way it was before I refactored things in #997. I tried hard to not break the interface, but turns out it was already borked. I'll work on a fix. Thanks for bringing this to our attention!

And just to be clear, you're basically wanting this constructor back so you can pass in your own SendGridClientOptions instance?

sendgrid-csharp/src/SendGrid/SendGridClient.cs

Lines 68 to 76 in 2310b6e

	/// <summary>
	/// Initializes a new instance of the <see cref="SendGridClient"/> class.
	/// </summary>
	/// <param name="options">A <see cref="SendGridClientOptions"/> instance that defines the configuration settings to use with the client </param>
	/// <returns>Interface to the Twilio SendGrid REST API</returns>
	public SendGridClient(SendGridClientOptions options)
	: this(null, options)
	{
	}