darkirc: fix update line in android.Dockerfile

bin/darkirc/android.Dockerfile

@@ -1,7 +1,7 @@
 FROM ubuntu
 ENV DEBIAN_FRONTEND noninteractive
 
-RUN apt update
+RUN apt-get update
 RUN apt install -yq openjdk-21-jre-headless openjdk-21-jdk-headless
 RUN apt install -yq wget unzip cmake file
 # For vendored openssl