Update CONTRIBUTORS.md, adding myself

张丹枫 · 张丹枫 · commit c4c9ab2736bd · 2020-05-20T22:26:58.000+08:00
diff --git a/CONTRIBUTORS.md b/CONTRIBUTORS.md
@@ -187,3 +187,6 @@ In chronological order:
 * Marius Hillenbrand <https://github.com/mhillenibm>
   * [2020-05-12] Revise dynamic architecture detection for IBM z
   * [2020-05-12] Add new sgemm and strmm kernel for IBM z14
+
+* Danfeng Zhang <https://github.com/craft-zhang>
+  * [2020-05-20] Improve performance of SGEMM and STRMM on Arm Cortex-A53
