Now add FR constraint files for #655

Dockerfile

@@ -1,10 +1,14 @@
+ARG DEBIAN_FRONTEND=noninteractive
 ARG GIT_IMAGE=bitnami/git:2.46.0
 ARG MAVEN_IMAGE=maven:3.9.8-eclipse-temurin-21
 ARG MAVEN_DEP_PLUGIN_VERSION=3.8.0
 ARG OSCAL_CLI_VERSION=2.0.2
 ARG OSCAL_CLI_INSTALL_PATH=/opt/oscal
+ARG FEDRAMP_AUTO_GIT_URL=https://github.com/GSA/fedramp-automation.git
+ARG FEDRAMP_AUTO_GIT_REF=feature/external-constraints
 
 FROM ${MAVEN_IMAGE} as cli_downloader
+ARG DEBIAN_FRONTEND=noninteractive
 ARG MAVEN_DEP_PLUGIN_VERSION
 ARG OSCAL_CLI_VERSION
 ARG OSCAL_CLI_INSTALL_PATH
@@ -18,6 +22,16 @@ RUN apt-get update -y && \
     -Dartifact=dev.metaschema.oscal:oscal-cli-enhanced:${OSCAL_CLI_VERSION}:zip:oscal-cli && \
     cd /opt/oscal-cli && unzip *.zip && rm -f *.zip
 
+FROM alpine:3.20.2 as fedramp_data_downloader
+ARG FEDRAMP_AUTO_GIT_URL
+ARG FEDRAMP_AUTO_GIT_REF
+RUN apk add --no-cache git && \
+    mkdir -p /usr/local/src && \
+    cd /usr/local/src && \
+    git clone ${FEDRAMP_AUTO_GIT_URL} && \
+    cd fedramp_automation && \
+    git checkout ${FEDRAMP_AUTO_GIT_REF}
+
 FROM cli_downloader
 LABEL org.opencontainers.image.authors="FedRAMP Automation Team <oscal@fedramp.gov>"
 LABEL org.opencontainers.image.documentation="https://automate.fedramp.gov"
@@ -29,6 +43,7 @@ LABEL org.opencontainers.image.licenses="CC0-1.0"
 ARG OSCAL_CLI_INSTALL_PATH
 COPY --from=cli_downloader /opt/oscal-cli /opt/
 RUN mkdir -p /opt/fedramp
+COPY --from=fedramp_data_downloader /usr/local/src/fedramp-automation/src/validations/constraints/*.xml /opt/fedramp
 ENV PATH="$PATH:/opt/oscal-cli/bin"
 WORKDIR /app
 ENTRYPOINT [ "/opt/oscal-cli/bin/oscal-cli" ]