doc: add section on install/upgrade/uninstall

Signed-off-by: Paul Bastide <[email protected]>

Author: prb112

README.md

@@ -30,6 +30,18 @@ ARCH=arm64 make dev-setup
 
 To install the code, use:
 
+``` shell
+helm install \
+  --create-namespace \
+  --namespace power-dra-driver \
+  power-dra-driver \
+  deployments/helm/power-dra-driver
+```
+
+## Upgrade
+
+To install the code, use:
+
 ``` shell
 helm upgrade \
   --create-namespace \