configurable source/branch with default

Signed-off-by: Shah, Karan <[email protected]>

openfl-docker/Dockerfile.base

@@ -2,6 +2,9 @@
 # SPDX-License-Identifier: Apache-2.0
 # ------------------------------------
 # OpenFL Base Image
+# $> docker build . -t openfl -f Dockerfile.base \
+#   [--build-arg BRANCH=develop] \
+#   [--build-arg SOURCE=https://github.com/USERNAME/openfl.git]
 # ------------------------------------
 FROM ubuntu:22.04 AS base
 
@@ -30,7 +33,9 @@ WORKDIR /home/user
 ENV PATH=/home/user/.local/bin:$PATH
 
 # Install OpenFL.
-RUN git clone --depth=1 --branch=develop https://github.com/securefederatedai/openfl.git && \
+ARG SOURCE=https://github.com/securefederatedai/openfl.git
+ARG BRANCH=develop
+RUN git clone --depth=1 --branch=${BRANCH} ${SOURCE} && \
     cd openfl && \
     pip install --no-cache-dir -U pip setuptools wheel && \
     pip install --no-cache-dir -e . && \