fix: always set str tag on string scalars

When yaml.v3 parses yaml, string scalars are tagged "!!str". It is
possible that we could parse a values file which sets the version to
eg 1.23 (a float), so that when we later update the value to "v2.4"
it can't be serialized. To protect against this, set the tag whenever
we create or update scalars that are explicitly intended to be strings.

Author: bewinsnw

pkg/argocd/update.go

@@ -627,6 +627,7 @@ func setHelmValue(currentValues *yaml.Node, key string, value interface{}) error
 				// If we're at the final key, set the value and return
 				if current.Kind == yaml.ScalarNode {
 					current.Value = value.(string)
+					current.Tag = "!!str"
 				} else {
 					return fmt.Errorf("unexpected type %s for key %s", nodeKindString(current.Kind), k)
 				}
@@ -640,10 +641,12 @@ func setHelmValue(currentValues *yaml.Node, key string, value interface{}) error
 					&yaml.Node{
 						Kind:  yaml.ScalarNode,
 						Value: k,
+						Tag:   "!!str",
 					},
 					&yaml.Node{
 						Kind:  yaml.ScalarNode,
 						Value: value.(string),
+						Tag:   "!!str",
 					},
 				)
 				return nil
@@ -652,6 +655,7 @@ func setHelmValue(currentValues *yaml.Node, key string, value interface{}) error
 					&yaml.Node{
 						Kind:  yaml.ScalarNode,
 						Value: k,
+						Tag:   "!!str",
 					},
 					&yaml.Node{
 						Kind:    yaml.MappingNode,