docs(readme): update readme for generator

[nellyk]

Added NODE_ENV as it is required for the one-app-generator to create a module

[oneamexbot]

☑️ Preflight Checklist:

All questions must be addressed before this PR can be merged.

• What is the communication plan for this change?
• Does any documentation need to be updated or added to account for this change? If so was it done already?
• What is the motivation for this change?
• Should these changes also be applied to a maintenance branch or any other long lived branch?
• How was this change tested?
• Does this change require cross browser checks? Why or why not?
• Does this change require a performance test prior to merging? Why or why not?
• Could this be considered a breaking change? Why or why not?
• Does the change impact caching?
• Does the change impact HTTP headers?
• Does the change have any new infrastructure requirements?
• Does the change affect other versions of the app?
• Does the change require additional environment variables?
• What is the impact to developers using the app?
• What is the change to the size of assets?
• Should integration tests be added to protect against future regressions on this change?

Generated by 🚫 dangerJS against 63c5f00

[10xLaCroixDrinker]

Commit type should be docs

[nellyk]

What is the communication plan for this change?N/A
Does any documentation need to be updated or added to account for this change? If so was it done already?N/A
What is the motivation for this change? For ensure correct installation when creating one-app modules
Should these changes also be applied to a maintenance branch or any other long lived branch?
How was this change tested?N/A
Does this change require cross browser checks? Why or why not?N/A
Does this change require a performance test prior to merging? Why or why not?N/A
Could this be considered a breaking change? Why or why not?Nope, updating the docs
Does the change impact caching?N/A
Does the change impact HTTP headers?N/A
Does the change have any new infrastructure requirements?N/A
Does the change affect other versions of the app?N/A
Does the change require additional environment variables?N/A
What is the impact to developers using the app?N/A
What is the change to the size of assets?N/A
Should integration tests be added to protect against future regressions on this change?N/A

[anescobar1991]

Good catch @nellyk!