libcoap: add licenses hash

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libcoap/libcoap.hash

@@ -1,2 +1,5 @@
 # Locally calculated
 sha256 f7e26dc232c177336474a14487771037a8fb32e311f5ccd076a00dc04b6d7b7a libcoap-v4.1.2.tar.gz
+sha256 28b61fbf3c5477611d7f6ead97d15348934496d27dca815b34d45e622730e72e COPYING
+sha256 d8c320ffc0030d1b096ae4732b50d2b811cf95e9a9b7377c1127b2563e0a0388 LICENSE.GPL
+sha256 9d5aeec17bdf82369bbe6e89efb07b7b35abefa044ea1d25cb2feeb70df1c208 LICENSE.BSD