Allow secrets to be excluded from release template inheritance (#1189)

* Allow secrets to be excluded from inheritance, small docs update

Signed-off-by: Alex Vorona <alex@vorona.com.ua>

* Fix typo in docs

Signed-off-by: Alex Vorona <alex@vorona.com.ua>

---------

Signed-off-by: Alex Vorona <alex@vorona.com.ua>

docs/writing-helmfile.md

@@ -104,6 +104,8 @@ releases:
   version: 0.3.2
   inherit:
   - template: default
+    except:
+      - secrets
 - name: kubernetes-dashboard
   version: 0.10.0
   inherit:
@@ -153,7 +155,7 @@ Thus we added a new way for inheritance, which uses the `inherit` field we intro
 
 See [issue helmfile/helmfile#435](https://github.com/helmfile/helmfile/issues/435#issuecomment-1362177510) for more context.
 
-You might also find [issue roboll/helmfile#428](https://github.com/roboll/helmfile/issues/428) useful for more context on how we originally designed the relase template and what it's supposed to solve.
+You might also find [issue roboll/helmfile#428](https://github.com/roboll/helmfile/issues/428) useful for more context on how we originally designed the release template and what it's supposed to solve.
 
 ## Layering Release Values
 

pkg/state/state_exec_tmpl.go

@@ -199,8 +199,10 @@ func (st *HelmState) releaseWithInheritedTemplate(r *ReleaseSpec, inheritancePat
 				src.SetValuesTemplate = nil
 			case "set":
 				src.SetValues = nil
+			case "secrets":
+				src.Secrets = nil
 			default:
-				return nil, fmt.Errorf("%q is not allowed under `inherit`. Allowed values are \"set\", \"setTemplate\", \"values\", \"valuesTemplate\", and \"labels\"", k)
+				return nil, fmt.Errorf("%q is not allowed under `inherit`. Allowed values are \"set\", \"setTemplate\", \"values\", \"valuesTemplate\", \"secrets\", and \"labels\"", k)
 			}
 
 			st.logger.Debugf("excluded field %q when inheriting template %q to release %q", k, templateName, r.Name)