package/network/services/dropbear: fix PKG_CPE_ID

package/network/services/dropbear: fix PKG_CPE_ID

cpe:/a:dropbear_ssh_project:dropbear_ssh is the correct CPE ID for dropbear:
https://nvd.nist.gov/products/cpe/search/results?keyword=cpe:2.3:a:dropbear_ssh_project:dropbear_ssh

Fixes: c61a2395140d92cdd37d3d6ee43a765427e8e318 (add PKG_CPE_ID ids to package and tools)

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/15290
Signed-off-by: Robert Marko <robimarko@gmail.com>
(cherry picked from commit 289f811abb4ace7aa08ae7bf85c0d4f9460f0802)
Link: https://github.com/openwrt/openwrt/pull/15881
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>