shairport-sync: update to v2.6

Closes https://github.com/openwrt/packages/pull/1869

Signed-off-by: Mike Brady <mikebrady@eircom.net>
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

sound/shairport-sync/Makefile

 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=shairport-sync
-PKG_VERSION:=2.4.1
-PKG_RELEASE:=2
+PKG_VERSION:=2.6
+PKG_RELEASE:=1
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL:=git://github.com/mikebrady/shairport-sync.git

sound/shairport-sync/files/shairport-sync.config

 	option resync_threshold '' # 2205
 	option log_verbosity '' # 0/1/2/3
 	option ignore_volume_control '' # no/yes
+	option volume_range_db '' # 30 to 150
 	# Latencies
 	option latencies_default '' # 88200
 	option latencies_itunes '' # 99400

sound/shairport-sync/files/shairport-sync.init

 		append_num "$cfg" "$conf_file" resync_threshold "resync_threshold"
 		append_num "$cfg" "$conf_file" log_verbosity "log_verbosity"
 		append_str "$cfg" "$conf_file" ignore_volume_control "ignore_volume_control"
+		append_num "$cfg" "$conf_file" volume_range_db "volume_range_db"
 		echo -e "};\n" >> $conf_file
 
 		# Latencies