Fix release script, rustler-codegen is not optional anymore

prepare_release.sh

@@ -36,7 +36,7 @@ echo "Bumping versions.."
 
 # Update versions in manifests
 sed -i "s/^version = \"[^\"]*\" # rustler version$/version = \"$VERSION\" # rustler version/" rustler/Cargo.toml
-sed -i "s/^rustler_codegen.*$/rustler_codegen = { path = \"..\/rustler_codegen\", version = \"$VERSION\", optional = true}/" rustler/Cargo.toml
+sed -i "s/^rustler_codegen.*$/rustler_codegen = { path = \"..\/rustler_codegen\", version = \"$VERSION\"}/" rustler/Cargo.toml
 sed -i "s/^version = \"[^\"]*\" # rustler_codegen version$/version = \"$VERSION\" # rustler_codegen version/" rustler_codegen/Cargo.toml
 sed -i "s/def rustler_version, do: \"[^\"]*\"$/def rustler_version, do: \"$VERSION\"/" rustler_mix/mix.exs rustler_mix/lib/rustler.ex
 sed -i "s/@version .*$/@version \"$VERSION\"/" rustler_mix/mix.exs