Use "uv" for building virtual environments

Change-Id: I5e24e82e6347d351cac71255904b44aa558d449b
diff --git a/images/manila/Dockerfile b/images/manila/Dockerfile
index 52ac86e..9a11c8f 100644
--- a/images/manila/Dockerfile
+++ b/images/manila/Dockerfile
@@ -6,8 +6,8 @@
 ARG MANILA_GIT_REF=09f3ab0a229362c00bb55f704cfeae43bccd3c8d
 ADD --keep-git-dir=true https://opendev.org/openstack/manila.git#${MANILA_GIT_REF} /src/manila
 RUN git -C /src/manila fetch --unshallow
-RUN --mount=type=cache,mode=0755,target=/root/.cache/pip,sharing=private <<EOF bash -xe
-pip3 install \
+RUN --mount=type=cache,target=/root/.cache/uv <<EOF bash -xe
+uv pip install \
     --constraint /upper-constraints.txt \
         /src/manila
 EOF