fix backend

Author: vincentsarago

pyproject.toml

@@ -53,8 +53,8 @@ Source = "https://github.com/developmentseed/titiler-stacapi"
 Changelog = "https://developmentseed.org/titiler-stacapi/release-notes/"
 
 [build-system]
-requires = ["pdm-pep517"]
-build-backend = "pdm.pep517.api"
+requires = ["pdm-backend"]
+build-backend = "pdm.backend"
 
 [tool.pdm.version]
 source = "file"