package/lpeg: add missing LPEG_LICENSE_FILES

The lpeg.html file declares the licensing terms at its bottom, so it
should work as a license file.

Signed-off-by: Nicolas Carrier <nicolas.carrier@orolia.com>
[yann.morin.1998@free.fr: use LPEG_SUBDIR]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit 52afc0b3b504c9616b3875dcdf67ab7be41455f5)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/lpeg/lpeg.hash

@@ -1,2 +1,4 @@
 # computed by luarocks/buildroot
 sha256  e0d0d687897f06588558168eeb1902ac41a11edd1b58f1aa61b99d0ea0abbfbc  lpeg-1.0.2-1.src.rock
+# computed locally
+sha256  2b80a8cce793e008ba433e5e0184f20aca4a67ec741439fafd86a874a6a91c49  lpeg-1.0.2/lpeg.html

package/lpeg/lpeg.mk

@@ -6,5 +6,6 @@
 
 LPEG_VERSION = 1.0.2-1
 LPEG_LICENSE = MIT
+LPEG_LICENSE_FILES = $(LPEG_SUBDIR)/lpeg.html
 
 $(eval $(luarocks-package))