usign: update to latest git HEAD

f1f65026a941 Always pad fingerprints to 16 characters

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
(cherry picked from commit e35e40ad824eab9d51cdd690fb747e576e01412f)

package/system/usign/Makefile

@@ -5,9 +5,9 @@ PKG_RELEASE:=1
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL=$(PROJECT_GIT)/usign.git
-PKG_SOURCE_DATE:=2019-09-21
-PKG_SOURCE_VERSION:=f34a383eeed6282fa16fb021157a60c75f33fdcd
-PKG_MIRROR_HASH:=74dc05f3ff24995193956a2803d20994fa6fce3d9e7d997002ee524618fbcec6
+PKG_SOURCE_DATE:=2020-05-23
+PKG_SOURCE_VERSION:=f1f65026a94137c91b5466b149ef3ea3f20091e9
+PKG_MIRROR_HASH:=3f6569a5e63fdfd032976ac0f79d736d3935101ac1b97fb370514b013c5e6bb6
 CMAKE_INSTALL:=1
 PKG_CHECK_FORMAT_SECURITY:=1
 PKG_USE_MIPS16:=0