update contributing.md (NVIDIA#449)

* update contributing.md

* update contributing.md

* address review

CONTRIBUTING.md

@@ -17,7 +17,7 @@ changes. CUB's tests and examples can be built by configuring Thrust with the
 CMake option `THRUST_INCLUDE_CUB_CMAKE=ON`.
 
 This process is described in more detail in Thrust's
-[CONTRIBUTING.md](https://github.com/NVIDIA/thrust/blob/main/CONTRIBUTING.md).
+[CONTRIBUTING.md](https://nvidia.github.io/thrust/contributing.html).
 
 The CMake options in the following section may be used to customize CUB's build
 process. Note that some of these are controlled by Thrust for compatibility and
@@ -89,4 +89,4 @@ The configuration options for CUB are:
 # Development Model
 
 CUB follows the same development model as Thrust, described
-[here](https://github.com/NVIDIA/thrust/blob/main/CONTRIBUTING.md#development-model).
+[here](https://nvidia.github.io/thrust/releases/versioning.html).