oxide: update to omicron version 53aea85 (#304)

Updated Omicron to
oxidecomputer/omicron@53aea85.
This pulls in the updating VPC firewall rules enums from
oxidecomputer/omicron#8194.

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

Author: sudomateo

.changelog/v0.6.0.toml

@@ -1,6 +1,6 @@
 [[breaking]]
-title = ""
-description = ""
+title = "`VpcFirewallRuleProtocol` type change"
+description = "Changed the type of the `VpcFirewallRuleProtocol` struct to reflect upstream API changes. [#304](https://github.com/oxidecomputer/oxide.go/pull/304)"
 
 [[features]]
 title = ""
@@ -12,4 +12,4 @@ description = ""
 
 [[enhancements]]
 title = ""
-description = ""
+description = ""

VERSION_OMICRON

@@ -1 +1 @@
-1b4b019
+53aea85

internal/generate/types.go

@@ -743,6 +743,11 @@ func createOneOf(s *openapi3.Schema, name, typeName string) ([]TypeTemplate, []E
 					field.Type = "any"
 				}
 
+				// Check if the field is nullable and use omitzero instead of omitempty.
+				if p.Value != nil && p.Value.Nullable {
+					field.SerializationInfo = fmt.Sprintf("`json:\"%s,omitzero\" yaml:\"%s,omitzero\"`", prop, prop)
+				}
+
 				fields = append(fields, field)
 
 				parsedProperties = append(parsedProperties, propertyName)