upgrade tini to latest version 0.18.0 and also added the option to send signal...

upgrade tini to latest version 0.18.0 and also added the option to send signal to all child group processes as mentioned in docs

https://github.com/krallin/tini#process-group-killing

base-notebook/Dockerfile

@@ -27,8 +27,8 @@ RUN echo "en_US.UTF-8 UTF-8" > /etc/locale.gen && \
     locale-gen
 
 # Install Tini
-RUN wget --quiet https://github.com/krallin/tini/releases/download/v0.10.0/tini && \
-    echo "1361527f39190a7338a0b434bd8c88ff7233ce7b9a4876f3315c22fce7eca1b0 *tini" | sha256sum -c - && \
+RUN wget --quiet https://github.com/krallin/tini/releases/download/v0.18.0/tini && \
+    echo "12d20136605531b09a2c2dac02ccee85e1b874eb322ef6baf7561cd93f93c855 *tini" | sha256sum -c - && \
     mv tini /usr/local/bin/tini && \
     chmod +x /usr/local/bin/tini
 
@@ -96,7 +96,7 @@ EXPOSE 8888
 WORKDIR $HOME
 
 # Configure container startup
-ENTRYPOINT ["tini", "--"]
+ENTRYPOINT ["tini", "-g", "--"]
 CMD ["start-notebook.sh"]
 
 # Add local files as late as possible to avoid cache busting

base-notebook/Dockerfile.ppc64le

@@ -30,10 +30,10 @@ RUN echo "LC_TYPE=en_US.UTF-8" >> /etc/default/locale
 RUN locale-gen en_US en_US.UTF-8
 
 #build and install Tini for ppc64le
-RUN wget https://github.com/krallin/tini/archive/v0.10.0.tar.gz && \
-    tar zxvf v0.10.0.tar.gz && \
-    rm -rf v0.10.0.tar.gz
-WORKDIR tini-0.10.0/
+RUN wget https://github.com/krallin/tini/archive/v0.18.0.tar.gz && \
+    tar zxvf v0.18.0.tar.gz && \
+    rm -rf v0.18.0.tar.gz
+WORKDIR tini-0.18.0/
 RUN cmake . && make install
 RUN mv ./tini /usr/local/bin/tini  && \
     chmod +x /usr/local/bin/tini
@@ -87,7 +87,7 @@ WORKDIR /home/$NB_USER/work
 RUN echo "ALL            ALL = (ALL) NOPASSWD: ALL" >> /etc/sudoers
 
 # Configure container startup
-ENTRYPOINT ["tini", "--"]
+ENTRYPOINT ["tini", "-g", "--"]
 CMD ["start-notebook.sh"]
 
 # Add local files as late as possible to avoid cache busting