Resize btrfs partition and filesystem (on a gpt disk)

This is sooooo easy.

• sudo umount /mnt/storage1/
• sudo parted /dev/sde
• (parted) print
• (parted) rm 1
• (parted) mkpart 1 ext2 1049kb 100%
• (parted) quit
• sudo mount /mnt/storage1/
• sudo btrfs filesystem resize max /mnt/storage1/
• done!