docker: Switch focal to lua5.2

For some reason I thought that this is not available anymore

docker: Switch focal to lua5.2
c19b5f23 · Jens Georg · 4a1b5c3c · c19b5f23
Commit c19b5f23 authored 4 years ago by Jens Georg
--- a/dockerfiles/focal.docker
+++ b/dockerfiles/focal.docker
@@ -24,7 +24,7 @@ RUN apt-get update && \
        graphviz \
        clang \
        libhdf5-dev \
-        liblua5.3-dev \
+        liblua5.2-dev \
        python3-sphinx \
        libgsl-dev \
        libssl-dev \