diff --git a/Dockerfile b/Dockerfile
index e303aaf..1b1cb15 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,7 +1,7 @@
 # syntax=docker/dockerfile:1
 
 ARG PYTHON_VERSION=3.9.6
-FROM python:${PYTHON_VERSION}-slim as base
+FROM python:${PYTHON_VERSION}-slim AS base
 
 # Prevents Python from writing pyc files.
 ENV PYTHONDONTWRITEBYTECODE=1