[Community] @Mousius -> Reviewer (apache#8764)

* adding Mousius to reviewers,  name update for Siva Reddy

* making Siva's name consistent

CONTRIBUTORS.md

@@ -68,7 +68,7 @@ We do encourage everyone to work anything they are interested in.
 - [Siju Samuel](https://github.com/siju-samuel): @siju-samuel - frontends
 - [Junru Shao](https://github.com/junrushao1994) (PMC): @junrushao1994 - relay, compiler
 - [Haichen Shen](https://github.com/icemelon9) (PMC): @icemelon9 - relay, topi
-- [Siva](https://github.com/srkreddy1238): @srkreddy1238 - frontends, golang
+- [Siva Rama Krishna Reddy](https://github.com/srkreddy1238): @srkreddy1238 - frontends, golang
 - [Zhixun Tan](https://github.com/phisiart): @phisiart - opengl, web
 - [Andrew Tulloch](https://github.com/ajtulloch): @ajtulloch - topi, compiler, runtime
 - [Luis Vega](https://github.com/vegaluisjose): @vegaluisjose - vta, chisel
@@ -136,7 +136,8 @@ We do encourage everyone to work anything they are interested in.
 - [Junru Shao](https://github.com/junrushao1994): @junrushao1994
 - [Haichen Shen](https://github.com/icemelon9): @icemelon9
 - [Xingjian Shi](https://github.com/sxjscience): @sxjscience
-- [Siva](https://github.com/srkreddy1238): @srkreddy1238
+- [Christopher Sidebottom](https://github.com/mousius): @mousius
+- [Siva Rama Krishna Reddy](https://github.com/srkreddy1238): @srkreddy1238
 - [Dmitriy Smirnov](https://github.com/d-smirnov): @d-smirnov
 - [Jon Soifer](https://github.com/soiferj): @soiferj
 - [Zhixun Tan](https://github.com/phisiart): @phisiart