test/docker: Upgrade docker image to include ethtool

Add `ethtool` to the Docker test environment to support
interface auto-negotiation tests.

Author: Ahmed Karic

test/.env

@@ -2,7 +2,7 @@
 # shellcheck disable=SC2034,SC2154
 
 # Current container image
-INFIX_TEST=ghcr.io/kernelkit/infix-test:2.2
+INFIX_TEST=ghcr.io/kernelkit/infix-test:2.3
 
 ixdir=$(readlink -f "$testdir/..")
 logdir=$(readlink -f "$testdir/.log")

test/docker/Dockerfile

@@ -26,7 +26,8 @@ RUN apk add --no-cache \
     openssl \
     curl \
     e2tools \
-    make
+    make \
+    ethtool
 
 ARG MTOOL_VERSION="3.0"
 RUN wget https://github.com/troglobit/mtools/releases/download/v3.0/mtools-$MTOOL_VERSION.tar.gz -O /tmp/mtools-$MTOOL_VERSION.tar.gz