Bump CI cmake version

From 3.20 to v3.21.3 on sulfur and nitrogen

tests/test_automation/github-actions/ci/run_step.sh

@@ -8,6 +8,15 @@ case "$1" in
   # Configure qmcpack using cmake out-of-source builds 
   configure)
     
+    if [[ "$HOST_NAME" =~ (sulfur) || "$HOST_NAME" =~ (nitrogen) ]]
+    then
+      echo "Use recent cmake v3.21.3"
+      export PATH=/opt/cmake-3.21.3-linux-x86_64/bin:$PATH
+      # Make current environment variables available to subsequent steps, 
+      # e.g. ctest
+      echo "PATH=$PATH" >> $GITHUB_ENV
+    fi
+    
     if [ -d ${GITHUB_WORKSPACE}/../qmcpack-build ]
     then
       echo "Found existing out-of-source build directory ${GITHUB_WORKSPACE}/../qmcpack-build, removing"