Pin NJOY version in CI to 2016.78

Author: paulromano

tools/ci/gha-install-njoy.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 set -ex
 cd $HOME
-git clone https://github.com/njoy/NJOY2016
+git clone -b 2016.78 https://github.com/njoy/NJOY2016
 cd NJOY2016
 mkdir build && cd build
 cmake -Dstatic=on .. && make 2>/dev/null && sudo make install