Avoid including cache and upload folder into JS minify path

[PedroErnst]

Updated the list of excluded folders for the JS minify utils.
Added 'upload'
Modified 'cache/' to 'cache'

Motivation and Context

Minify JS would fail sometimes if it encountered unexpected contents in the upload folder.
Also the cache folder was not being excluded because of a trailing slash character.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Final checklist

• My code follows the code style of this project found here.
• My change requires a change to the documentation.
• I have read the How to Contribute guidelines.