ci: fix conditional check in changed-files action (#133)

The change resolves an issue with the usage of `changed_files` GH action
used in the workflow. The method `only_changed` returns a string type
and not a boolean.

Author: inianv

.github/workflows/build.yml

@@ -33,7 +33,7 @@ jobs:
             config.json
 
       - name: Extract version and create tag
-        if: steps.changed-files.outputs.only_changed
+        if: steps.changed-files.outputs.only_changed == 'true'
         run: |
           git config user.name "github-actions[bot]"
           git config user.email "github-actions[bot]@users.noreply.github.com"