Add contributors table to README

Author: Caitlin Bales (MSFT)

README.md

@@ -98,6 +98,17 @@ For known issues, see [issues](https://github.com/MicrosoftGraph/msgraph-sdk-jav
 
 The Microsoft Graph SDK is open for contribution. Please read how to contribute to this project [here](https://github.com/microsoftgraph/msgraph-sdk-java/blob/master/CONTRIBUTING.md).
 
+Thanks to everyone who has already devoted time to improving the library:
+
+<!-- ALL-CONTRIBUTORS-LIST:START  -->
+<!-- prettier-ignore -->
+| [<img src="https://avatars.githubusercontent.com/u/2273297?v=4" width="100px;"/><br /><sub><b>Caitlin Bales</b></sub>](https://developer.microsoft.com/graph)<br />[💬](#question-cbales "Answering Questions") [💻](https://github.com/microsoftgraph/msgraph-sdk-java/commits?author=cbales "Code") [📖](https://github.com/microsoftgraph/msgraph-sdk-java/wiki "Documentation") [👀](#review-cbales "Reviewed Pull Requests") [⚠️](https://github.com/microsoftgraph/msgraph-sdk-java/commits?author=cbales "Tests")| [<img src="https://avatars.githubusercontent.com/u/318187?v=4" width="100px;"/><br /><sub><b>David Moten</b></sub>](https://github.com/davidmoten)<br /> [🐛](https://github.com/microsoftgraph/msgraph-sdk-java/issues?q=is%3Aissue+author%3Adavidmoten "Bug reports") [💻](https://github.com/microsoftgraph/msgraph-sdk-java/commits?author=davidmoten "Code") [📖](https://github.com/microsoftgraph/msgraph-sdk-java/commit/87389b5a4240072e3f2226a2f04f089916ffed0b#diff-04c6e90faac2675aa89e2176d2eec7d8 "Documentation") [🤔](#ideas-davidmoten "Ideas & Planning") [👀](#review-davidmoten "Reviewed Pull Requests") [⚠️](https://github.com/microsoftgraph/msgraph-sdk-java/commits?author=davidmoten "Tests") | [<img src="https://avatars.githubusercontent.com/u/8527305?v=4" width="100px;"/><br /><sub><b>Michael Mainer</b></sub>](https://developer.microsoft.com/graph)<br /> [💬](#question-cbales "Answering Questions") [🤔](#ideas-MIchaelMainer "Ideas & Planning") [👀](#review-MIchaelMainer "Reviewed Pull Requests") | [<img src="https://avatars.githubusercontent.com/u/27295799?v=4" width="100px;"/><br /><sub><b>Linda Caputo</b></sub>](https://developer.microsoft.com/graph)<br />[📖](https://github.com/microsoftgraph/msgraph-sdk-java/wiki "Documentation") | [<img src="https://avatars.githubusercontent.com/u/8884923?v=4" width="100px;"/><br /><sub><b>John Austin</b></sub>](https://developer.microsoft.com/graph)<br />[🐛](https://github.com/microsoftgraph/msgraph-sdk-java/issues "Bug reports") | [<img src="https://avatars.githubusercontent.com/u/3460953?v=4" width="100px;"/><br /><sub><b>Dmitry Pimenov</b></sub>](https://developer.microsoft.com/graph)<br />[🤔](#ideas-dpim "Ideas & Planning") | [<img src="https://avatars.githubusercontent.com/u/1427840?v=4" width="100px;"/><br /><sub><b>Jonathan Giles</b></sub>](https://github.com/JonathanGiles)<br />[🤔](#ideas-JonathanGiles "Ideas & Planning") |
+| :---: | :---: | :---: | :---: | :---: | :---: | :---: |
+|  [<img src="https://avatars.githubusercontent.com/u/881767?v=4" width="100px;"/><br /><sub><b>Martin Sawicki</b></sub>](https://github.com/martinsawicki)<br />[🤔](#ideas-martinsawicki "Ideas & Planning") | [<img src="https://avatars.githubusercontent.com/u/29152134?v=4" width="100px;"/><br /><sub><b>Louis Maresca</b></sub>](https://github.com/LouMM)<br />[🤔](#ideas-LouMM "Ideas & Planning") [👀](#review-LouMM "Reviewed Pull Requests") |
+<!-- ALL-CONTRIBUTORS-LIST:END -->
+
+This project follows the [all-contributors](https://github.com/kentcdodds/all-contributors) specification. Contributions of any kind are welcome!
+
 ## 7. Supported Java Versions
 The Microsoft Graph SDK for Java library is supported at runtime for Java 7+ and [Android API revision 15](http://source.android.com/source/build-numbers.html) and greater.