fix dockerfile

Author: john-david3

test/docker/nginx-official-image/deb/Dockerfile

@@ -4,6 +4,7 @@ ARG IMAGE_PATH
 FROM ${CONTAINER_NGINX_IMAGE_REGISTRY}${IMAGE_PATH}:${TAG} AS install
 LABEL maintainer="NGINX Docker Maintainers <docker-maint@nginx.com>"
 
+ARG TAG
 ARG OS_RELEASE
 ARG OS_VERSION
 ARG DEBIAN_FRONTEND=noninteractive
@@ -17,10 +18,13 @@ COPY ./build/${PACKAGE_NAME}.${CONTAINER_OS_TYPE} /agent/build/${PACKAGE_NAME}.$
 
 RUN  apt-get update \
     && apt install --no-install-recommends --no-install-suggests --allow-downgrades -y /agent/build/${PACKAGE_NAME}.${CONTAINER_OS_TYPE} \
-    &&  rm /agent/build/${PACKAGE_NAME}.${CONTAINER_OS_TYPE}
+    &&  rm /agent/build/${PACKAGE_NAME}.${CONTAINER_OS_TYPE} 
+
+RUN echo "$TAG"
 
-RUN if [ "$TAG" == "mainline-bookworm" || "$TAG" == "stable-bookworm" ]; then \
-     curl -O https://${PACKAGES_REPO}/nginx-agent/${OS_RELEASE}/pool/agent/n/nginx-agent/nginx-agent_3.2.1~bookworm_${ARCH}.deb fi
+RUN if [ "$TAG" = "mainline-bookworm" ] || [ "$TAG" = "stable-bookworm" ]; then \
+        curl -O https://${PACKAGES_REPO}/nginx-agent/debian/pool/agent/n/nginx-agent/nginx-agent_3.2.1~bookworm_${ARCH}.deb; \
+    fi
 
 RUN unlink /var/log/nginx/access.log
 RUN unlink /var/log/nginx/error.log