update to smaller logo

Signed-off-by: Ashley Davis <[email protected]>

Author: SgtCoDFish

README.md

@@ -1,5 +1,5 @@
 <p align="center">
-  <img src="https://raw.githubusercontent.com/cert-manager/cert-manager/d7a3a3976785bd5717d9d06b115878feaf257597/logo/logo.png" height="241" width="250" alt="cert-manager project logo" />
+  <img src="https://raw.githubusercontent.com/cert-manager/cert-manager/d53c0b9270f8cd90d908460d69502694e1838f5f/logo/logo-small.png" height="256" width="256" alt="cert-manager project logo" />
 </p>
 
 # cert-manager-csi-lib