Use Doxygen 1.12.0 for github pages builds

Author: Matthew-Whitlock

.github/scripts/build-gh-pages.sh

@@ -1,8 +1,16 @@
 #!/bin/bash
 
+
 set -e
+
+echo "Installing apt packages"
 sudo apt-get update >/dev/null
-sudo apt-get install -y git cmake doxygen graphviz >/dev/null
+sudo apt-get install -y wget git cmake graphviz >/dev/null
+
+echo "Installing Doxygen"
+wget https://www.doxygen.nl/files/doxygen-1.12.0.linux.bin.tar.gz >/dev/null
+tar -xzf doxygen-1.12.0.linux.bin.tar.gz >/dev/null
+export PATH="$PWD/doxygen-1.12.0/bin:$PATH"
 
 #List of branches to build docs for
 #TODO: Remove doxygen branch once tested