validate step title at plan time to avoid unexpected apply errors (#250)

* validate step title at plan time to avoid unexpected apply errors

* update docs

---------

Co-authored-by: Chris McNabb <[email protected]> @raizyr

Author: Eyal-Shalev

docs/resources/port_action.md

@@ -514,7 +514,7 @@ Optional:
 Required:
 
 - `order` (List of String) The order of the properties in this step
-- `title` (String) The step's title
+- `title` (String) The step's title (max 25 characters)
 
 
 <a id="nestedatt--self_service_trigger--user_properties"></a>

port/action/schema.go

@@ -133,8 +133,11 @@ func ActionSchema() map[string]schema.Attribute {
 					NestedObject: schema.NestedAttributeObject{
 						Attributes: map[string]schema.Attribute{
 							"title": schema.StringAttribute{
-								MarkdownDescription: "The step's title",
+								MarkdownDescription: "The step's title (max 25 characters)",
 								Required:            true,
+								Validators: []validator.String{
+									stringvalidator.LengthAtMost(25),
+								},
 							},
 							"order": schema.ListAttribute{
 								MarkdownDescription: "The order of the properties in this step",