fix: typo in docs Barman Cloud helm install (#872)

Signed-off-by: Andreas Salhus Bakseter <6720179+bakseter@users.noreply.github.com>
Co-authored-by: Itay Grudev <itay@verito.digital>

Author: bakseter

README.md

@@ -60,7 +60,7 @@ for more information about that.
 
 ```console
 helm repo add cnpg https://cloudnative-pg.github.io/charts
-helm upgrade --install plugin-baman-cloud \
+helm upgrade --install plugin-barman-cloud \
   --namespace cnpg-system \
   cnpg/plugin-barman-cloud
 ```