[MINOR] Fix docker image build by introducing bash (apache#15347)

The base eclipse-temuring:21-jre-alpine image got modified and had `bash` removed from it. This broke our build, since downstream steps utilizing bash scripts depended on it. This patch explicitly installs bash

docker/jvm/Dockerfile

@@ -28,7 +28,7 @@ COPY jsa_launch /etc/kafka/docker/jsa_launch
 RUN set -eux ; \
     apk update ; \
     apk upgrade ; \
-    apk add --no-cache wget gcompat gpg gpg-agent procps netcat-openbsd; \
+    apk add --no-cache wget gcompat gpg gpg-agent procps netcat-openbsd bash; \
     mkdir opt/kafka; \
     wget -nv -O kafka.tgz "$kafka_url"; \
     wget -nv -O kafka.tgz.asc "$kafka_url.asc"; \
@@ -62,7 +62,7 @@ LABEL org.label-schema.name="kafka" \
 RUN set -eux ; \
     apk update ; \
     apk upgrade ; \
-    apk add --no-cache wget gpg gpg-agent gcompat; \
+    apk add --no-cache wget gpg gpg-agent gcompat bash; \
     mkdir opt/kafka; \
     wget -nv -O kafka.tgz "$kafka_url"; \
     wget -nv -O kafka.tgz.asc "$kafka_url.asc"; \