rebase to alpine v3.19.1

Dockerfile

 ARG BASE_REGISTRY=registry1.dso.mil
-ARG BASE_IMAGE=ironbank/redhat/ubi/ubi9-minimal
-ARG BASE_TAG=9.3
+ARG BASE_IMAGE=ironbank/opensource/alpinelinux/alpine
+ARG BASE_TAG=3.19.1
 
 FROM velero/velero-plugin-for-csi:v0.7.0 as base
 
 FROM ${BASE_REGISTRY}/${BASE_IMAGE}:${BASE_TAG}
 
-RUN microdnf update -y && \
-    microdnf upgrade -y && \
-    microdnf clean all && \
-    rm -rf /var/cache/dnf
 
-RUN mkdir /plugins
+RUN apk update && \
+    apk upgrade && \
+    apk add --no-cache bash && \
+    rm -rf /var/cache/apk/* && \
+    addgroup -S velero && \
+    adduser --no-create-home --system velero --ingroup velero --shell /sbin/nologin
 
 COPY --from=base /plugins/velero-plugin-for-csi /plugins
 
-USER nobody
+USER velero
 
 HEALTHCHECK NONE