ucert: update to latest git HEAD

e4bd927 cast ucert_argv to proper type when passing to execv

Fixes warnings:

warning: passing argument 2 of 'execv' from incompatible pointer type
[-Wincompatible-pointer-types]
  254 |       execv(usign_argv[0], usign_argv)

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
(cherry picked from commit 9c272dd3e4)

package/system/ucert/Makefile

@@ -5,9 +5,9 @@ PKG_RELEASE:=1
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL=$(PROJECT_GIT)/project/ucert.git
-PKG_SOURCE_DATE:=2018-09-18
-PKG_SOURCE_VERSION:=e1c722b1b6cbf2527b3178342464e56b97825874
-PKG_MIRROR_HASH:=36dcca7c2d649a6c34a8daaaef4698fbeb808fd6580c6bfb1ca35f4f06825d17
+PKG_SOURCE_DATE:=2019-11-29
+PKG_SOURCE_VERSION:=e4bd927cc7c756de5f3005824b63a7a6d827e1ee
+PKG_MIRROR_HASH:=cc6853e861110dd89cc8bd909c5f02150c2c3f9a77de66017393515644a7ac36
 
 CMAKE_INSTALL:=1
 PKG_CHECK_FORMAT_SECURITY:=1