Install python3-venv in Ubuntu containers

Author: vkarak

ci-scripts/dockerfiles/Lmod-base.dockerfile

@@ -9,7 +9,7 @@ RUN \
   apt-get -y update && \
   apt-get -y install ca-certificates && \
   update-ca-certificates && \
-  apt-get -y install gcc make git python3 python3-pip
+  apt-get -y install gcc make git python3 python3-pip python3-venv
 
 # Required utilities
 RUN apt-get -y install wget

ci-scripts/dockerfiles/Lmod77-base.dockerfile

@@ -15,7 +15,7 @@ RUN \
   apt-get -y update && \
   apt-get -y install ca-certificates && \
   update-ca-certificates && \
-  apt-get -y install gcc make git python3 python3-pip
+  apt-get -y install gcc make git python3 python3-pip python3-venv
 
 # Required utilities
 RUN apt-get -y install wget

ci-scripts/dockerfiles/Spack.dockerfile

@@ -19,7 +19,7 @@ RUN \
   apt-get -y install gcc && \
   apt-get -y install make && \
   apt-get -y install git && \
-  apt-get -y install python3 python3-pip
+  apt-get -y install python3 python3-pip python3-venv
 
 # Install ReFrame from the current directory
 COPY --chown=rfmuser . /home/rfmuser/reframe/

ci-scripts/dockerfiles/Tmod4-base.dockerfile

@@ -9,7 +9,7 @@ RUN \
   apt-get -y update && \
   apt-get -y install ca-certificates && \
   update-ca-certificates && \
-  apt-get -y install gcc make git python3 python3-pip
+  apt-get -y install gcc make git python3 python3-pip python3-venv
 
 # Required utilities
 RUN apt-get -y install wget