[patch] update and correct readme for CF metadata Webpack plugin

[Rick-Kirkham]

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Please add '[major]', '[minor]', or [patch] to the title to indicate the impact the change has on the code. Please also provide the following information.

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Change Description:

update and correct readme for CF metadata Webpack plugin

1. Do these changes impact command syntax of any of the packages? (e.g., add/remove command, add/remove a command parameter, or update required parameters) If Yes, briefly describe what is impacted. NO

2. Do these changes impact documentation? (e.g., a tutorial on https://learn.microsoft.com/office/dev/add-ins/overview/office-add-ins) If Yes, briefly describe what is impacted. NO

If you answered yes to any of these please do the following:

Include 'Rick-Kirkham' in the review Make sure the README file is correct

Validation/testing performed:

Describe manual testing done. 

[millerds]

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