apply the mtime given by the gopro to the written files

[klaernie]

set the mtime of downloaded files

The gopro already tells us what the mtime of the files should be, so we should set the mtime of our newly mades copies to the respective timestamp.

This allows applications like Google Photos to have the actual timestamp available, when the file was written, instead of reading the timestamp when the files were downloaded from the camera.

Please be aware that this is the first time I'm ever handling golang code, so if any of this is not acceptable or not in proper style please tell me - I'm currently in the "I know barely enough to be dangerous" phase. ;)

Type:

• [x] Bug fix
• [ ] New feature
• [ ] Breaking change
• [ ] Documentation

Camera:

• [x] GoPro
• [ ] Insta360
• [ ] DJI
• [ ] Android
• [ ] This PR adds a new camera

Component:

• [ ] Core logic
• [x] Import
• [ ] Merging
• [ ] Firmware Update
• [ ] Video Manipulation

Checklist before approval:

• Linter pass
• Build pass