Add PingTouGe contribution credit.

CONTRIBUTORS.md

@@ -190,4 +190,7 @@ In chronological order:
   * [2020-09-07] Fix builds with clang on IBM z, including dynamic architecture support
 
 * Danfeng Zhang <https://github.com/craft-zhang>
-  * [2020-05-20] Improve performance of SGEMM and STRMM on Arm Cortex-A53
+  * [2020-05-20] Improve performance of SGEMM and STRMM on Arm Cortex-A53
+
+* PingTouGe Semiconductor Co., Ltd.
+  * [2020-10] Add RISC-V Vector (0.7.1) support. Optimize BLAS kernels for Xuantie C910