docs: properly capitalize brands GitHub and SendGrid (#742)

.github/PULL_REQUEST_TEMPLATE

@@ -23,4 +23,4 @@ Closes #2
 -
 - 
 
-If you have questions, please send an email to [Twilio SendGrid](mailto:dx@sendgrid.com), or file a Github Issue in this repository.
+If you have questions, please send an email to [Twilio SendGrid](mailto:dx@sendgrid.com), or file a GitHub Issue in this repository.

CONTRIBUTING.md

@@ -42,7 +42,7 @@ A software bug is a demonstrable issue in the code base. In order for us to diag
 
 Before you decide to create a new issue, please try the following:
 
-1. Check the Github issues tab if the identified issue has already been reported, if so, please add a +1 to the existing post.
+1. Check the GitHub issues tab if the identified issue has already been reported, if so, please add a +1 to the existing post.
 2. Update to the latest version of this code and check if issue has already been fixed
 3. Copy and fill in the Bug Report Template we have provided below
 
@@ -197,4 +197,4 @@ If you have any additional questions, please feel free to [email](mailto:dx@send
 <a name="code-reviews"></a>
 ## Code Reviews
 
-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 [great information on how to review a Pull Request](https://help.github.com/articles/about-pull-request-reviews/).
+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 [great information on how to review a Pull Request](https://help.github.com/articles/about-pull-request-reviews/).

lib/contacts/README.md

@@ -1,6 +1,6 @@
 # Recipients Helper
 
-**This helper allows you to quickly and easily build a subscription form to add contacts to your contactdb in Sendgrid.**
+**This helper allows you to quickly and easily build a subscription form to add contacts to your contactdb in SendGrid.**
 
 ## Quick Start
 

test/unit/AttachmentsTest.php

@@ -26,7 +26,7 @@ class AttachmentsTests extends TestCase
     public function testWillEncodeNonBase64String() {
 
         $attachment = new Attachment();
-        $testString = 'Twilio Sendgrid is awesome!';
+        $testString = 'Twilio SendGrid is awesome!';
 
         $attachment->setContent($testString);
 
@@ -36,7 +36,7 @@ public function testWillEncodeNonBase64String() {
     public function testWillNotEncodeBase64String() {
 
         $attachment = new Attachment();
-        $testString = base64_encode('Twilio Sendgrid is awesome!');
+        $testString = base64_encode('Twilio SendGrid is awesome!');
 
         $attachment->setContent($testString);