Fix absolute image path

Dockerfile

@@ -29,7 +29,7 @@ FROM ${SELKIES_JS_IMAGE} AS selkies-js-interposer
 # Build the current nvidia-vaapi-driver without retaining build dependencies
 # -----------------------------------------------------------------------------
 
-FROM ubuntu:${DISTRIB_RELEASE} AS nvidia-vaapi-builder
+FROM docker.io/library/ubuntu:${DISTRIB_RELEASE} AS nvidia-vaapi-builder
 
 ARG DEBIAN_FRONTEND=noninteractive
 ARG NVIDIA_VAAPI_DRIVER_VERSION
@@ -77,7 +77,7 @@ RUN set -eux; \
 # Final image
 # -----------------------------------------------------------------------------
 
-FROM ubuntu:${DISTRIB_RELEASE}
+FROM docker.io/library/ubuntu:${DISTRIB_RELEASE}
 
 ARG DEBIAN_FRONTEND=noninteractive
 ARG DISTRIB_RELEASE