[Enterprise Bot Generator][TypeScript] Incorrect name of gitignore file

[Batta32]

Project
Enterprise Bot Template

Description
Generating a bot using yo botbuilder-enterprise, creates a gitignore file without the dot prefix.

To Reproduce

1. Go to AI/templates/Enterprise-Template/src/typescript/generator-botbuilder-enterprise
2. Run npm pack and save the name of the package generated
3. Run npm i -g <name_of_your_package>
4. Run yo botbuilder-enterprise wherever you want to create your bot
5. Check that the gitignore file does not contain a dot prefix

Expected behavior
The generated bot should contain a .gitignore file

Screenshots
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Additional context
As stated in npm/npm#1862, when publishing a package (or using npm pack and installing it locally) the .gitignore file is replaced with a .npmignore file, that's why the gitignore file inside the template shouldn't be renamed to .gitignore.