docs: Updated mysql secret generation command (acryldata#438)

* docs: Updated mysql secret generation command

By the change of mysql helm chart version the provided secret
has at least three keys:
- mysql-root-password
- mysql-replication-password
- mysql-password

Otherwise mysql chart won't install.
More information: https://artifacthub.io/packages/helm/bitnami/mysql#mysql-common-parameters

* fix: Applied requested changes

README.md

@@ -43,7 +43,7 @@ separately on-prem or leveraged as managed services.
 Assuming kubectl context points to the correct kubernetes cluster, first create kubernetes secrets that contain MySQL and Neo4j passwords. 
 
 ```(shell)
-kubectl create secret generic mysql-secrets --from-literal=mysql-root-password=datahub
+kubectl create secret generic mysql-secrets --from-literal=mysql-root-password=datahub --from-literal=mysql-password=datahub
 kubectl create secret generic neo4j-secrets --from-literal=neo4j-password=datahub --from-literal=NEO4J_AUTH=neo4j/datahub
 ```