Fix json-cpp variable name

docker/code-analysis/Dockerfile

@@ -172,13 +172,13 @@ RUN \
     make && \
     make install
 
-# nlohmann
-ARG NLOHMANN_VERSION=be61ad147000be4802173d0d118fd1b8109b4668
+# json-cpp
+ARG JSON_CPP_VERSION=be61ad147000be4802173d0d118fd1b8109b4668
 RUN \
     cd /opt/dev && \
     git clone https://github.com/nlohmann/json.git && \
     cd json && \
-    git checkout ${NLOHMANN_VERSION} && \
+    git checkout ${JSON_CPP_VERSION} && \
     mkdir build && \
     cd build && \
     cmake .. && \