scaffolder-backend: fix file path resolution for templates with a file location

Co-authored-by: Johan Haals <johan.haals@gmail.com>

.changeset/slimy-singers-return.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-scaffolder-backend': patch
+---
+
+Fixed file path resolution for templates with a file location

plugins/scaffolder-backend/src/scaffolder/tasks/TemplateConverter.ts

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { resolve as resolvePath } from 'path';
+import { resolve as resolvePath, dirname } from 'path';
 import { JsonValue } from '@backstage/config';
 import { TemplateEntityV1alpha1 } from '@backstage/catalog-model';
 import { Logger } from 'winston';
@@ -39,7 +39,7 @@ export function templateEntityToSpec(
 
   let url: string;
   if (protocol === 'file') {
-    const path = resolvePath(location, template.spec.path || '.');
+    const path = resolvePath(dirname(location), template.spec.path || '.');
 
     url = `file://${path}`;
   } else {