package/ccache: bump to version 3.7.4

package/ccache: bump to version 3.7.4

- Update CCACHE_SITE to github.

- The hash of the license file is updated. There were two changes:

  * The reference to the credits.html file changed from
    ccache.samba.org to ccache.dev

  * The MIT license text for minitrace.[ch] was added, but it doesn't
    change the fact that the whole is under GPL-3.0, and we anyway
    already had "GPL-3.0, others" in CCACHE_LICENSE

Signed-off-by: Asaf Kahlon <asafka7@gmail.com>
[Thomas: update the license file hash]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>