[jvm-packages] Launch dev jvm image under my user (#4676)

Co-authored-by: Philip Hyunsu Cho <chohyu01@cs.washington.edu>

jvm-packages/dev/Dockerfile

@@ -47,4 +47,12 @@ ENV JAVA_HOME=/usr/lib/jvm/java
 RUN \
     pip install numpy pytest scipy scikit-learn wheel kubernetes urllib3==1.22 awscli
 
+ENV GOSU_VERSION 1.10
+
+# Install lightweight sudo (not bound to TTY)
+RUN set -ex; \
+    wget -O /usr/local/bin/gosu "https://github.com/tianon/gosu/releases/download/$GOSU_VERSION/gosu-amd64" && \
+    chmod +x /usr/local/bin/gosu && \
+    gosu nobody true
+
 WORKDIR /xgboost