DEVELOPERS: add missing ending slash

This was missing in commit
08a0dea25f4e92ac5aa474876f706ddb9452fe2b ("package/bootgen: add
bootgen host package")

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

DEVELOPERS

@@ -2175,7 +2175,7 @@ F:	configs/zynq_zc706_defconfig
 F:	configs/zynqmp_zcu102_defconfig
 F:	configs/zynqmp_zcu106_defconfig
 F:	configs/zynqmp_kria_kv260_defconfig
-F:	package/bootgen
+F:	package/bootgen/
 
 N:	Nicola Di Lieto <nicola.dilieto@gmail.com>
 F:	package/uacme/