Updated how chromium-browser is installed.

unity-command/Dockerfile

@@ -1,9 +1,11 @@
 #Arg is replaced with the desired Unity container.
-ARG IMAGE=unityci/base:latest
+ARG IMAGE=unityci/editor:2023.1.16f1-windows-mono-3
 FROM ${IMAGE}
 
-RUN apt update
-RUN apt install -y wget chromium-browser
+RUN apt-get update
+RUN apt-get install -y software-properties-common apt-transport-https wget chromium-browser
+RUN add-apt-repository -y ppa:savoury1/chromium
+RUN apt-get update && apt-get install -y chromium-browser
 
 #ADD https://minio.studiowhy.net/hackmd/UnityBuilder /usr/local/bin/
 COPY UnityBuilder /usr/local/bin/