push validation of prefex

Author: Jwels1

github/resource_github_repository_autolink_reference.go

@@ -65,10 +65,11 @@ func resourceGithubRepositoryAutolinkReference() *schema.Resource {
 				Description: "The repository name",
 			},
 			"key_prefix": {
-				Type:        schema.TypeString,
-				Required:    true,
-				ForceNew:    true,
-				Description: "This prefix appended by a number will generate a link any time it is found in an issue, pull request, or commit",
+				Type:             schema.TypeString,
+				Required:         true,
+				ForceNew:         true,
+				Description:      "This prefix appended by a number will generate a link any time it is found in an issue, pull request, or commit",
+				ValidateDiagFunc: validation.ToDiagFunc(validation.StringMatch(regexp.MustCompile(`^.*?[^\d]$`), "must not end with a number")),
 			},
 			"target_url_template": {
 				Type:             schema.TypeString,