[pkg] don't update the systray repo

It will fail in the CI or if you have a custom version.

Makefile

@@ -48,7 +48,7 @@ build_win: staging\nssm.exe helper_win systray_win
 build_cross_win: staging/nssm.exe
 	echo "!define VERSION $(VERSION)" > $(STAGING)/version.nsh
 	$(CROSS_FLAGS) $(MAKE) helper_win
-	$(CROSS_FLAGS) go get -tags "standalone" -u $(SYSTRAY)
+	$(CROSS_FLAGS) go get -tags "standalone" $(SYSTRAY)
 	$(CROSS_FLAGS) go build -tags "standalone" -ldflags "-H windowsgui -s -w -X main.version=$(VERSION)" -o $(STAGING)/$(SYSTRAY_BIN).exe $(SYSTRAY)
 	upx $(STAGING)/$(SYSTRAY_BIN).exe
 	mkdir -p dist