chore: update GitHub branch references to use HEAD

CONTRIBUTING.md

@@ -68,7 +68,7 @@ Next, update your Environment (user space) with your SENDGRID_USERNAME and SENDG
 
 ##### Execute: #####
 
-See the [examples folder](https://github.com/sendgrid/smtpapi-csharp/tree/master/Smtpapi/Example) to get started quickly.
+See the [examples folder](Smtpapi/Example) to get started quickly.
 
 <a name="understanding-the-codebase"></a>
 ## Understanding the Code Base
@@ -92,9 +92,9 @@ Source code
 
 All PRs require passing tests before the PR will be reviewed.
 
-All test files are in the [`Smtpapi/HeaderTests`](https://github.com/sendgrid/smtpapi-csharp/tree/master/Smtpapi/HeaderTests) directory.
+All test files are in the [`Smtpapi/HeaderTests`](Smtpapi/HeaderTests) directory.
 
-For the purposes of contributing to this repo, please update the [`TestHeader.cs`](https://github.com/sendgrid/smtpapi-csharp/blob/master/test/Smtpapi/HeaderTests/TestHeader.cs) file with unit tests as you modify the code.
+For the purposes of contributing to this repo, please update the [`TestHeader.cs`](Smtpapi/HeaderTests/TestHeader.cs) file with unit tests as you modify the code.
 
 From the Visual Studio menu: `Tests->Run->All Tests`
 
@@ -144,7 +144,7 @@ Generally, we follow the style guidelines as suggested by the official language.
 5. Locally merge (or rebase) the upstream development branch into your topic branch:
 
    ```bash
-   git pull [--rebase] upstream master
+   git pull [--rebase] upstream main
    ```
 
 6. Push your topic branch up to your fork:
@@ -154,7 +154,7 @@ Generally, we follow the style guidelines as suggested by the official language.
    ```
 
 7. [Open a Pull Request](https://help.github.com/articles/using-pull-requests/)
-    with a clear title and description against the `master` branch. All tests must be passing before we will review the PR.
+    with a clear title and description against the `main` branch. All tests must be passing before we will review the PR.
 
 ## Code Reviews<a name="code-reviews"></a>
 If you can, please look at open PRs and review them. Give feedback and help us merge these PRs much faster! If you don't know how, Github has some <a href="https://help.github.com/articles/about-pull-request-reviews/">great information on how to review a Pull Request.</a>

FIRST_TIMERS.md

@@ -39,7 +39,7 @@ git checkout -b <topic-branch-name>
  6. __Locally merge (or rebase)__ the upstream development branch into your topic branch:
 ```
 
-    git pull [--rebase] upstream master
+    git pull [--rebase] upstream main
 
 ```
 7. __Push__ your topic branch up to your fork:
@@ -49,7 +49,7 @@ git push origin <topic-branch-name>
 
 ```
 8. __[Open a Pull Request](https://help.github.com/articles/creating-a-pull-request/#changing-the-branch-range-and-destination-repository/)__
- with a clear title and description against the `master` branch. All tests must be passing before we will review the PR.
+ with a clear title and description against the `main` branch. All tests must be passing before we will review the PR.
 ### Important notice
 Before creating a pull request, make sure that you respect the repository's constraints regarding contributions. You can find them in the [CONTRIBUTING.md](./CONTRIBUTING.md) file.
 ## Repositories with Open, Easy, Help Wanted, Issue Filters

README.md

@@ -1,6 +1,6 @@
-![SendGrid Logo](https://uiux.s3.amazonaws.com/2016-logos/email-logo%402x.png)
+![SendGrid Logo](twilio_sendgrid_logo.png)
 
-[![Travis Badge](https://travis-ci.org/sendgrid/smtpapi-csharp.svg?branch=master)](https://travis-ci.org/sendgrid/smtpapi-csharp)
+[![Travis Badge](https://travis-ci.org/sendgrid/smtpapi-csharp.svg?branch=main)](https://travis-ci.org/sendgrid/smtpapi-csharp)
 [![Email Notifications Badge](https://dx.sendgrid.com/badge/csharp)](https://dx.sendgrid.com/newsletter/csharp)
 [![Twitter Follow](https://img.shields.io/twitter/follow/sendgrid.svg?style=social&label=Follow)](https://twitter.com/sendgrid)
 [![GitHub contributors](https://img.shields.io/github/contributors/sendgrid/smtpapi-csharp.svg)](https://github.com/sendgrid/smtpapi-csharp/graphs/contributors)
@@ -11,7 +11,7 @@
 # Announcements
 **The default branch name for this repository has been changed to `main` as of 07/27/2020.**
 
-All updates to this module are documented in our [CHANGELOG](https://github.com/sendgrid/smtpapi-csharp/blob/master/CHANGELOG.md).
+All updates to this module are documented in our [CHANGELOG](CHANGELOG.md).
 
 # Table of Contents
 - [Installation](#installation)
@@ -51,7 +51,7 @@ PM> Install-Package SendGrid.SmtpApi
 
 Once you have the library properly referenced in your project, you can include calls to them in your code.
 
-For a sample implementation, check the [Example](https://github.com/sendgrid/smtpapi-csharp/blob/master/Smtpapi/Example/Program.cs)
+For a sample implementation, check the [Example](Smtpapi/Example/Program.cs)
 
 <a name="quick-start"></a>
 # Quick Start
@@ -117,7 +117,7 @@ mail.Headers.Add("X-SMTPAPI", header.JsonString());
 # Usage
 
 - [SendGrid Docs](https://sendgrid.com/docs/API_Reference/SMTP_API/index.html)
-- [Example Code](https://github.com/sendgrid/smtpapi-csharp/blob/master/Smtpapi/Example/Program.cs)
+- [Example Code](Smtpapi/Example/Program.cs)
 
 <a name="roadmap"></a>
 # Roadmap
@@ -127,13 +127,13 @@ If you are interested in the future direction of this project, please take a loo
 <a name="contribute"></a>
 # How to Contribute
 
-We encourage contribution to our projects, please see our [CONTRIBUTING](https://github.com/sendgrid/smtpapi-csharp/blob/master/CONTRIBUTING.md) guide for details.
+We encourage contribution to our projects, please see our [CONTRIBUTING](CONTRIBUTING.md) guide for details.
 
 Quick links:
 
-- [Feature Request](https://github.com/sendgrid/smtpapi-csharp/blob/master/CONTRIBUTING.md)
-- [Bug Reports](https://github.com/sendgrid/smtpapi-csharp/blob/master/CONTRIBUTING.md#submit-a-bug-report)
-- [Improvements to the Codebase](https://github.com/sendgrid/smtpapi-csharp/blob/master/CONTRIBUTING.md#improvements-to-the-codebase)
+- [Feature Request](CONTRIBUTING.md)
+- [Bug Reports](CONTRIBUTING.md#submit-a-bug-report)
+- [Improvements to the Codebase](CONTRIBUTING.md#improvements-to-the-codebase)
 
 <a name="about"></a>
 # About