Update Dockerfile for Codespaces

Author: stefmolin

.devcontainer/Dockerfile

@@ -1,17 +1,11 @@
-# https://github.com/microsoft/vscode-dev-containers/blob/main/containers/python-3-miniconda/.devcontainer/base.Dockerfile
+# https://github.com/devcontainers/images/tree/main/src/miniconda
 ARG VARIANT=3
-FROM mcr.microsoft.com/vscode/devcontainers/miniconda:${VARIANT}
-
-# Install mamba for faster install
-ENV MAMBA_EXE="/opt/mambaforge/bin/mamba"
-RUN cd /tmp \
-    && curl -L -O "https://github.com/conda-forge/miniforge/releases/latest/download/Mambaforge-$(uname)-$(uname -m).sh" \
-    && sudo bash Mambaforge-$(uname)-$(uname -m).sh -b -p /opt/mambaforge
+FROM mcr.microsoft.com/devcontainers/miniconda:${VARIANT}
 
 # Create the conda environment
 COPY environment.yml /tmp/conda-tmp/
-RUN $MAMBA_EXE env create --file /tmp/conda-tmp/environment.yml --prefix /home/vscode/.conda/envs/data_viz_workshop \
-    && $MAMBA_EXE init
+RUN conda env create --file /tmp/conda-tmp/environment.yml --prefix /home/vscode/.conda/envs/data_viz_workshop \
+    && conda init
 
 # Update PATH for Jupyter editing option
 ENV PATH="/home/vscode/.conda/envs/data_viz_workshop/bin:${PATH}"