[rpms/calibre] f43: add missing tzlocal requires

[Michael J Gruber <mjg@fedoraproject.org>]

            A new commit has been pushed.

            Repo   : rpms/calibre
            Branch : f43
            Commit : 68a0b2dc47f6e3c9afe5e74ee5ce325d4ea4f6eb
            Author : Michael J Gruber <mjg@fedoraproject.org>
            Date   : 2026-05-19T18:11:44+02:00
            Stats  : +1/-0 in 1 file(s)
            URL    : https://src.fedoraproject.org/rpms/calibre/c/68a0b2dc47f6e3c9afe5e74ee5ce325d4ea4f6eb?branch=f43

            Log:
            add missing tzlocal requires

Otherwise:

```
$ calibre
Traceback (most recent call last):
  File "/usr/bin/calibre", line 21, in <module>
    sys.exit(calibre())
             ~~~~~~~^^
  File "/usr/lib64/calibre/calibre/gui_launch.py", line 72, in calibre
    from calibre.gui2.main import main
  File "/usr/lib64/calibre/calibre/gui2/__init__.py", line 88, in <module>
    from calibre.utils.date import UNDEFINED_DATE
  File "/usr/lib64/calibre/calibre/utils/date.py", line 14, in <module>
    from calibre.utils.iso8601 import UNDEFINED_DATE, local_tz, utc_tz
  File "/usr/lib64/calibre/calibre/utils/iso8601.py", line 8, in <module>
    import tzlocal
ModuleNotFoundError: No module named 'tzlocal'
```

---
diff --git a/calibre.spec b/calibre.spec
index d64e0e0..2df8c8d 100644
--- a/calibre.spec
+++ b/calibre.spec
@@ -150,6 +150,7 @@ Requires:       python3dist(html2text)
 Requires:       python3dist(markdown) >= 3.0
 Requires:       python3dist(pychm)
 Requires:       python3dist(pyqt6-sip)
+Requires:       python3dist(tzlocal)
 %if %{undefined flatpak}
 Requires:       udisks2
 %endif