docs: update URLs from stainlessapi.com to stainless.com (#67)

More details at https://www.stainless.com/changelog/stainless-com

README.md

@@ -6,7 +6,7 @@ The Gitpod Python library provides convenient access to the Gitpod REST API from
 application. The library includes type definitions for all request params and response fields,
 and offers both synchronous and asynchronous clients powered by [httpx](https://github.com/encode/httpx).
 
-It is generated with [Stainless](https://www.stainlessapi.com/).
+It is generated with [Stainless](https://www.stainless.com/).
 
 ## Documentation
 

SECURITY.md

@@ -2,9 +2,9 @@
 
 ## Reporting Security Issues
 
-This SDK is generated by [Stainless Software Inc](http://stainlessapi.com). Stainless takes security seriously, and encourages you to report any security vulnerability promptly so that appropriate action can be taken.
+This SDK is generated by [Stainless Software Inc](http://stainless.com). Stainless takes security seriously, and encourages you to report any security vulnerability promptly so that appropriate action can be taken.
 
-To report a security issue, please contact the Stainless team at security@stainlessapi.com.
+To report a security issue, please contact the Stainless team at security@stainless.com.
 
 ## Responsible Disclosure