package/tiff: security bump to version 4.7.0
For the release note, see:
http://www.simplesystems.org/libtiff/releases/v4.7.0.html
This commit also adds the _SOURCE variable, to switch to the xz
archive, which saves ~1.5MB. The _SITE url is also updated to switch
to the https protocol.
This commit also adds a comment in the hash file about pgp signature
veritication.
Fixes:
- https://nvd.nist.gov/vuln/detail/CVE-2023-6277
- https://nvd.nist.gov/vuln/detail/CVE-2023-52356
- https://nvd.nist.gov/vuln/detail/CVE-2024-7006
Signed-off-by: Julien Olivain <ju.o@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>