Update release script.

In new gradle version, the output is in the
release/ subdirectory.

Author: rdoeffinger

release.sh

@@ -1,5 +1,5 @@
 VER=$(grep versionName AndroidManifest.xml | sed -e 's/.*"\(.*\)".*/v\1/')
 cp build/outputs/mapping/release/mapping.txt mapping-$VER.txt
-cp Dictionary-release.apk Dictionary-$VER.apk
+cp release/Dictionary-release.apk Dictionary-$VER.apk
 gpg -a --detach-sign Dictionary-$VER.apk
 git tag -u 06D4D9C7 "$VER"