declare correct type (number) for publish:gitlab output.projectId

Signed-off-by: Matt Benson <gudnabrsam@gmail.com>

.changeset/quiet-needles-impress.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-scaffolder-backend-module-gitlab': minor
+---
+
+declare correct type (number) for publish:gitlab output.projectId

plugins/scaffolder-backend-module-gitlab/src/actions/gitlab.ts

@@ -294,7 +294,7 @@ export function createPublishGitlabAction(options: {
           },
           projectId: {
             title: 'The ID of the project',
-            type: 'string',
+            type: 'number',
           },
           commitHash: {
             title: 'The git commit hash of the initial commit',