docs(redpanda): update sasl authentication option to use scram sha 256 (#3126)

* Update options.go

Highlight that the sasl authentication uses scram sha 256 (I spent some time trying to connect with 512 until I realize my mistake)

* update docs

Author: peczenyj

docs/modules/redpanda.md

@@ -99,7 +99,7 @@ E.g. `WithSuperusers("superuser-1", "superuser-2")`.
 
 - Since testcontainers-go <a href="https://github.com/testcontainers/testcontainers-go/releases/tag/v0.20.0"><span class="tc-version">:material-tag: v0.20.0</span></a>
 
-The `WithEnableSASL()` option enables SASL scram sha authentication. By default, no authentication (plaintext) is used.
+The `WithEnableSASL()` option enables SASL scram sha 256 authentication. By default, no authentication (plaintext) is used.
 When setting an authentication method, make sure to add users as well and authorize them using the `WithSuperusers()` option.
 
 #### WithEnableKafkaAuthorization

modules/redpanda/options.go

@@ -15,7 +15,7 @@ type options struct {
 	KafkaEnableAuthorization bool
 
 	// KafkaAuthenticationMethod is either "none" for plaintext or "sasl"
-	// for SASL (scram) authentication.
+	// for SASL (scram sha 256) authentication.
 	KafkaAuthenticationMethod string
 
 	// SchemaRegistryAuthenticationMethod is either "none" for no authentication
@@ -78,6 +78,9 @@ func (o Option) Customize(*testcontainers.GenericContainerRequest) error {
 	return nil
 }
 
+// WithNewServiceAccount includes a new user with username (key) and password (value)
+// that shall be created, so that you can use these to authenticate against
+// Redpanda (either for the Kafka API or Schema Registry HTTP access).
 func WithNewServiceAccount(username, password string) Option {
 	return func(o *options) {
 		o.ServiceAccounts[username] = password
@@ -92,7 +95,7 @@ func WithSuperusers(superusers ...string) Option {
 	}
 }
 
-// WithEnableSASL enables SASL scram sha authentication.
+// WithEnableSASL enables SASL scram sha 256 authentication.
 // By default, no authentication (plaintext) is used.
 // When setting an authentication method, make sure to add users
 // as well as authorize them using the WithSuperusers() option.