Add support for custom volume mounts in container_opts

[jirikuncar]

Overview of issue:

Add an extra mount for node_modules.

Describe the results you received:

node_modules are modified when running generated command.

Describe the results you expected:

node_modules won't be affected after running generate command.

Additional information you deem important (e.g. issue happens only occasionally):

[github-actions[bot]]

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