add missing library needed by mamba, reenable docker build

.github/workflows/CI.yaml

@@ -107,7 +107,7 @@ jobs:
     runs-on: ubuntu-latest
     needs: test
     name: Build Docker Image
-    if: ${{ false }}
+    if: github.event_name != 'pull_request'
 
     steps:
       - name: Set up Docker Buildx

Dockerfile

@@ -1,4 +1,4 @@
-ARG PY_VERSION=3.8
+ARG PY_VERSION=3.10
 FROM continuumio/miniconda3:4.10.3-alpine AS builder
 
 EXPOSE 8888
@@ -17,6 +17,9 @@ WORKDIR /mbuild
 # Create a group and user
 RUN addgroup -S anaconda && adduser -S anaconda -G anaconda
 
+# install the libarchive package needed by mamba
+RUN apk update && apk add libarchive
+
 RUN conda update conda -yq && \
   conda config --set always_yes yes --set changeps1 no && \
   . /opt/conda/etc/profile.d/conda.sh && \