Changed Kafka topic name validation (#1051)

* Changed Kafka topic name validation so that capital characters are also allowed
* Removing support for \ in Kafka topic name
* Using raw string some specific sequences

pkg/apis/fission.io/v1/validation.go

@@ -36,7 +36,8 @@ const (
 
 var (
 	validAzureQueueName = regexp.MustCompile("^[a-z0-9][a-z0-9\\-]*[a-z0-9]$")
-	validKafkaTopicName = regexp.MustCompile("^[a-z0-9][a-z0-9\\-._]*[a-z0-9]$")
+	// Need to use raw string to support escape sequence for - & . chars
+	validKafkaTopicName = regexp.MustCompile(`^[a-zA-Z0-9][a-zA-Z0-9\-\._]*[a-zA-Z0-9]$`)
 )
 
 type (