Bump in conda version and mamba solver (#1298)

Author: dtpryce

mlserver/cli/constants.py

@@ -1,12 +1,14 @@
 DockerfileName = "Dockerfile"
 DockerfileTemplate = """
-FROM continuumio/miniconda3:4.12.0 AS env-builder
+FROM continuumio/miniconda3:22.11.1 AS env-builder
 SHELL ["/bin/bash", "-c"]
 
 ARG MLSERVER_ENV_NAME="mlserver-custom-env" \\
     MLSERVER_ENV_TARBALL="./envs/base.tar.gz"
 
 RUN conda config --add channels conda-forge && \\
+    conda install conda-libmamba-solver && \\
+    conda config --set solver libmamba && \\
     conda install conda-pack
 
 # The `[]` character range will ensure that Docker doesn't complain if the
@@ -24,7 +26,7 @@
             conda env create \
                 --name $MLSERVER_ENV_NAME \\
                 --file $envFile; \\
-            conda-pack --ignore-missing-files --quiet \
+            conda-pack --ignore-missing-files \
                 -n $MLSERVER_ENV_NAME \\
                 -o $MLSERVER_ENV_TARBALL; \\
         fi \\