package/nettle: security bump to version 3.7.2

package/nettle: security bump to version 3.7.2

Fix CVE-2021-20305: A flaw was found in Nettle in versions before 3.7.2,
where several Nettle signature verification functions (GOST DSA, EDDSA &
ECDSA) result in the Elliptic Curve Cryptography point (ECC) multiply
function being called with out-of-range scalers, possibly resulting in
incorrect results. This flaw allows an attacker to force an invalid
signature, causing an assertion failure or possible validation. The
highest threat to this vulnerability is to confidentiality, integrity,
as well as system availability.

https://git.lysator.liu.se/nettle/nettle/-/blob/nettle_3.7.2_release_20210321/NEWS

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>