package/mongoose: bump to version 6.13

package/mongoose: bump to version 6.13

For some reason, the hash of the Github-provided tarball for mongoose
6.7 has changed. The actual contents are the same between the old and
new tarballs, only the order of the files is changed.

However, changing the hash would break older Buildroot releases
(because sources.buildroot.net would pick up the tarball with the new
hash, and old Buildroot releases would no longer be able to pick up
the tarball with the old hash, neither from Github nor from the
Buildroot mirror).

So, we simply bump to a newer version of mongoose. This way, old
Buildroot releases will continue to fetch Mongoose 6.7 from the
Buildroot mirror, with the old hash matching. New Buildroot releases
will be using the new Mongoose version, with a correct hash that
allows to download from Github successfully.

The hash of the license file has changed, due to a change in the
copyright years.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>