Update Kokkos library in LAMMPS to v3.0

lib/kokkos/cmake/compile_tests/clang_omp.cpp

@@ -0,0 +1,9 @@
+#include <omp.h>
+
+int main(int argc, char** argv) {
+  int thr = omp_get_num_threads();
+  if (thr > 0)
+    return thr;
+  else
+    return 0;
+}