[actions] in actions manual.sh, export USECCACHE=1 to enable ccache i…

…n madgraph4gpu - and also dump ccache status before/after the builds

.github/workflows/manual.sh

@@ -100,17 +100,23 @@ if [ "$stage" == "tput" ]; then
   echo
   echo "ccache --version | head -1"
   ccache --version | head -1
+  # Dump ccache status before the builds
   echo
-  echo "ccache -s"
+  echo "ccache -s (before the builds)"
   ccache -s
   # Configure CXX
   echo
   echo "g++ --version"
   g++ --version
   export CXX=g++
   # Build and test
+  export USECCACHE=1 # enable ccache in madgraph4gpu builds
   echo "./tput/teeThroughputX.sh -makej -ggtt -makeclean"
   ./tput/teeThroughputX.sh -makej -ggtt -makeclean
+  # Dump ccache status after the builds
+  echo
+  echo "ccache -s (after the builds)"
+  ccache -s
 fi
 
 # Finalise