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This release fix some minor issues and adds the --manifest command.

• restrict ssh capability to the agent socket.
• home volume is set to the namespace name if a namespace is defined.
• allow passing args directly to a command: podenv nix:github:podenv/devenv#emacs --version
• fix syscaps argument for bwrap.
• use system chcon to set label.
• add --manifest argument to show every configuration context.

This is the first release of podenv.