setting the user with UID 1000

(cherry picked from commit b9abb24)

Dockerfile

@@ -22,14 +22,8 @@ RUN gpg --keyserver https://secchannel.rsk.co/SUPPORT.asc --recv-keys 1DC9157991
 FROM eclipse-temurin:17-jre@sha256:38e0afc86a10bf4cadbf1586fb617b3a9a4d09c9a0be882e29ada4ed0895fc84
 LABEL org.opencontainers.image.authors="ops@rootstocklabs.com"
 
-RUN mkdir -p /var/lib/rsk && \
-    chown -R 1000:1000 /var/lib/rsk
-
-USER ubuntu
-
-RUN mkdir -p /var/lib/rsk/.rsk && \
-    chown -R ubuntu:ubuntu /var/lib/rsk && \
-    chmod -R 755 /var/lib/rsk/.rsk
+RUN useradd -ms /sbin/nologin -d /var/lib/rsk -o -u 1000 rsk
+USER rsk
 
 WORKDIR /var/lib/rsk
 COPY --from=build --chown=rsk:rsk /home/rsk/rsk.jar ./