add step to fix name for upload

[benjamink]

Fix firmware file output name to something standard so the deploy-nightly workflow step can find it when build targets don't match matrix item names.

Also removed the date stamp from the file name for Andy.

NOTE: need to manually delete the old asset files with the date from the Nightly Builds Release since the new files will have different names so won't overwrite current ones.

[tschak909]

Thank you!