Use ninja -k option in CI

Some users of the OAI CI complain that since we build with -Werror, it
is difficult to see all warnings/errors and fix them, necessitating
multiple attempts at times to see all warnings. To allow them to see
more warnings, use ninja option -k10 to keep going after errors, and
show more errors at once.

docker/Dockerfile.build.rocky

@@ -38,6 +38,7 @@ RUN /bin/sh oaienv && \
     CXXFLAGS="-Werror -fstack-protector-strong" CFLAGS="-Werror -fstack-protector-strong" ./build_oai -c --ninja \
       --eNB --gNB --RU --UE --nrUE \
       --build-lib "telnetsrv enbscope uescope nrscope" \
+      --build-tool-opt -k10 \
       -w USRP -t Ethernet \
       --noavx512 && \
     echo "---- ldd on executables ----" && \