Update json-c library version to 0.18 in Dockerfiles and fetch script

debian13/Dockerfile

@@ -493,7 +493,7 @@ RUN --mount=type=bind,from=sources,source=librdkafka-v2.15.0.tar.gz,target=/tmp/
     && cmake --build build --parallel "$(nproc)" --target install \
     && rm -rf build src
 
-RUN --mount=type=bind,from=sources,source=json-c-json-c-0.19-20260627.tar.gz,target=/tmp/json-c.tar.gz \
+RUN --mount=type=bind,from=sources,source=json-c-json-c-0.18-20240915.tar.gz,target=/tmp/json-c.tar.gz \
     mkdir src \
     && tar --extract --gzip --file=/tmp/json-c.tar.gz --directory=src --strip-components=1 \
     && cmake -G Ninja -S src -B build -DCMAKE_BUILD_TYPE=Release \