opkg: update to latest Git HEAD

f2166a8 libopkg: implement lightweight package listing logic
cf4554d libopkg: support passing callbacks to feed parsing functions
2a0210f opkg-cl: don't read feeds on opkg update
b6f1967 libopkg: use xsystem() to spawn opkg-key
60b9af2 file_util.c: refactor and fix checksum_hex2bin()
206ebae file_util.c: fix possible bad memory access in file_read_line_alloc()

Signed-off-by: Jo-Philipp Wich <[email protected]>

package/system/opkg/Makefile

@@ -14,9 +14,9 @@ PKG_FLAGS:=essential
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL:=https://git.openwrt.org/project/opkg-lede.git
-PKG_SOURCE_DATE:=2020-01-25
-PKG_SOURCE_VERSION:=c09fe2098718807ddbca13ee36e3e38801822946
-PKG_MIRROR_HASH:=b2fba519fb3bf2da2e325a33eee951b85c7c1886e48ebaac3892435a71ae33d5
+PKG_SOURCE_DATE:=2020-05-07
+PKG_SOURCE_VERSION:=f2166a89b7e96e2c60002959731eebc5f45fa318
+PKG_MIRROR_HASH:=67e55cd9fb93bb5b62e2c7b11946483b5570287bd1504aa2a3886d11f8b750b9
 
 PKG_LICENSE:=GPL-2.0
 PKG_LICENSE_FILES:=COPYING