fix: updated rock with new non-root user config

canonical/seldon-core-operator#133

Summary of changes:
- Updated rockcraft.yaml with new run-user option to run as non-root.
- Updated import procedure.

seldon-core-operator/rockcraft.yaml

@@ -14,12 +14,12 @@ version: v1.15.0_22.04_1 # version format: <KF-upstream-version>_<base-version>_
 license: Apache-2.0
 build-base: ubuntu:22.04
 base: bare
+run-user: _daemon_
 services:
   seldon-core:
     override: replace
     summary: "seldon-core service"
     startup: enabled
-    user: ubuntu
     command: "/manager --enable-leader-election --webhook-port 4443"
 platforms:
   amd64:
@@ -99,18 +99,6 @@ parts:
       wget -qO mitchellh-gox.tar.gz https://github.com/mitchellh/gox/archive/master.tar.gz
       wget -qO mozilla-tls-observatory.tar.gz https://github.com/mozilla/tls-observatory/archive/master.tar.gz
 
-  non-root-user:
-    plugin: nil
-    overlay-script: |
-      # Create a user in the $CRAFT_OVERLAY chroot
-      mkdir -p $CRAFT_OVERLAY/etc
-      chmod 755 $CRAFT_OVERLAY/etc
-      groupadd -R $CRAFT_OVERLAY -g 1001 ubuntu
-      useradd -R $CRAFT_OVERLAY -M -r -u 1001 -g ubuntu ubuntu
-    override-prime: |
-      craftctl default
-      chown -R 1001:1001 tmp/operator-resources
-
   security-team-requirement:
     plugin: nil
     after: [seldon-core-operator, mpl-deps]

seldon-core-operator/tox.ini

@@ -63,7 +63,7 @@ commands =
                     print(CheckRock("rockcraft.yaml").get_version())'\'') && \
              sudo skopeo --insecure-policy copy oci-archive:$ROCK.rock docker-daemon:$ROCK:$VERSION && \
              docker save $ROCK > $ROCK.tar && \
-             microk8s ctr image import $ROCK.tar && \
+             microk8s ctr image import $ROCK.tar --digests=true && \
              # replace upstream-source with local ROCK image \
              yq e -i ".resources.oci-image.upstream-source=\"$ROCK:$VERSION\"" {env:LOCAL_CHARM_DIR}/metadata.yaml'
     # run charm integration test with rock