Repro files

devcontainer.json

{
	"name": "Test",
	"build": {
		"dockerfile": "Dockerfile",
		"args": { 
			// Update 'VARIANT' to pick a .NET Core version: 2.1, 3.1, 5.0
			"VARIANT": "3.1",
			// Options
			"INSTALL_NODE": "false",
			"NODE_VERSION": "lts/*",
			"INSTALL_AZURE_CLI": "true"
		}
	},

	// Set *default* container specific settings.json values on container create.
	"settings": {
		"terminal.integrated.shell.linux": "/bin/bash"
	},

	// Add the IDs of extensions you want installed when the container is created.
	"extensions": [
		"ms-dotnettools.csharp"
	],
  
	"remoteUser": "vscode"
}

Dockerfile

# See here for image contents: https://github.com/microsoft/vscode-dev-containers/tree/v0.155.1/containers/dotnet/.devcontainer/base.Dockerfile

# [Choice] .NET version: 5.0, 3.1, 2.1
ARG VARIANT="3.1"
FROM mcr.microsoft.com/vscode/devcontainers/dotnetcore:0-${VARIANT}
RUN sudo apt-key adv --refresh-keys --keyserver keyserver.ubuntu.com

# [Option] Install Node.js
ARG INSTALL_NODE="true"
ARG NODE_VERSION="lts/*"
RUN if [ "${INSTALL_NODE}" = "true" ]; then su vscode -c "umask 0002 && . /usr/local/share/nvm/nvm.sh && nvm install ${NODE_VERSION} 2>&1"; fi

# [Option] Install Azure CLI
ARG INSTALL_AZURE_CLI="false"
COPY library-scripts/azcli-debian.sh /tmp/library-scripts/
RUN if [ "$INSTALL_AZURE_CLI" = "true" ]; then bash /tmp/library-scripts/azcli-debian.sh; fi \
    && apt-get clean -y && rm -rf /var/lib/apt/lists/* /tmp/library-scripts

# [Optional] Uncomment this section to install additional OS packages.
# RUN apt-get update && export DEBIAN_FRONTEND=noninteractive \
#     && apt-get -y install --no-install-recommends <your-package-list-here>

# [Optional] Uncomment this line to install global node packages.
# RUN su vscode -c "source /usr/local/share/nvm/nvm.sh && npm install -g <your-package-here>" 2>&1