Release version 14. (#43)

* Fix issue with APT::Update::Post-Invoke. (#40)

* Fix issue with APT::Update::Post-Invoke.

E: Problem executing scripts APT::Update::Post-Invoke 'rm -f
/var/cache/apt/archives/*.deb /var/cache/apt/archives/partial/*.deb
/var/cache/apt/*.bin || true'
E: Sub-process returned an error code

* Update docker related error on Jammy.

* Prepare for next development cycle for version 0.8.14 [full build]

* Travis ubuntu jammy

.travis.yml

@@ -1,4 +1,4 @@
-dist: focal
+dist: jammy
 
 language: java
 

VERSION

@@ -1 +1 @@
-0.8.13
+0.8.14

projects/jupyterhub-singleuser/Dockerfile

@@ -2,9 +2,6 @@ FROM jupyter/datascience-notebook:lab-3.6.3
 
 USER root
 
-
-RUN sed -i -e 's/^APT/# APT/' -e 's/^DPkg/# DPkg/' /etc/apt/apt.conf.d/docker-clean
-
 RUN apt-get update && \
     apt-get install -y vim curl sudo libneon27-gnutls-dev po4a automake && \
     rm -rf /var/lib/apt/lists/* /var/log/dpkg.log /var/log/apt/*