[osk-sdl] Update to 0.51 (#862)

aports/main/osk-sdl/APKBUILD

 pkgname=osk-sdl
-pkgver=0.50
+pkgver=0.51
 pkgrel=0
 pkgdesc="Onscreen keyboard for unlocking LUKS devices"
 url="https://github.com/postmarketOS/osk-sdl"
@@ -23,4 +23,4 @@ package() {
     install -D -m755 "${srcdir}/${pkgname}-${pkgver}"/osk.conf \
         "$pkgdir"/etc/osk.conf
 }
-sha512sums="08b6b5c428302808166f6cc31a9fb778606e46226cb4d05100e829056d6ca598611f7456846cb086a4c5189e643509be7f4f160861f6bd508aed70c809c7994e  osk-sdl-0.50-0.tar.gz"
+sha512sums="0adf343d9641654dec5be8c3ba06d1b7bbd7738f0c1a5afa6672e3824b08c66985103fe8ba807da63fcf83d2a640b73b7bd449ec1805fc152522190debb65c87  osk-sdl-0.51-0.tar.gz"