package/caps: fix license string

The correct license string is `GPL-3.0+` not `GPLv3`.

Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/caps/caps.mk

@@ -7,7 +7,7 @@
 CAPS_VERSION = 0.9.26
 CAPS_SOURCE = caps_$(CAPS_VERSION).tar.bz2
 CAPS_SITE = http://quitte.de/dsp
-CAPS_LICENSE = GPLv3
+CAPS_LICENSE = GPL-3.0+
 CAPS_LICENSE_FILES = COPYING
 
 # Need to pass TARGET_CONFIGURE_OPTS in the environment to not