fix: do not match {}, only ${}

[aturetta]

Pull request #2 was right in principle, but contained a syntax error ($ must be escaped in a RE)

if you add the following line to your test file, you can see what is the effect with or without this patch

file-format-template = /data/system/{os}/object/{obj-id}/

[anandjoshi91]

Thanks for the fix.

LGTM

[anandjoshi91]

Fix applied to the latest release

pip install property==2.4