fix: ensure OpenAPI artefact paths exist in before_scripts

.gitlab/openapi-generator.gitlab-ci.yml

@@ -69,6 +69,8 @@ openapi:schema:version:
   image:
     name: $OPENAPI_GENERATOR_YQ_IMAGE
     entrypoint: [""]
+  before_script:
+    - mkdir -p $(dirname "$OPENAPI_GENERATOR_SCHEMA_VERSION_ARTIFACT")
   script:
     - yq -r ".info.version" "$OPENAPI_GENERATOR_SCHEMA_ARTIFACT_PATH" >"$OPENAPI_GENERATOR_SCHEMA_VERSION_ARTIFACT"
   artifacts: