package/oniguruma: fix license hash

Year has been updated when bumping to 6.9.2:
https://github.com/kkos/oniguruma/commit/73ac6e6a236c12ff62f48e56da536b5c9a1c543b

Fixes:
 - http://autobuild.buildroot.org/results/551b3f12867e27b1a9f784099cad1e439d50089f

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

package/oniguruma/oniguruma.hash

@@ -1,3 +1,3 @@
 # Locally calculated
 sha256  3b568a9050839e7828b2f2d5bc9cd3650979b6b54a080f54c515320dddda06b0  oniguruma-6.9.2.tar.gz
-sha256  84e55812150474adf4170d4656744dfcc5f260ff7602e447a70bf13c56203e4b  COPYING
+sha256  ae266a1ad1c2ef50baf14a1a2993e926cd46d09c6cc8b0b3a8498e44da2746b8  COPYING