[cpm] Updates to tclap and vtkdiff
Fixes compilation issue with tclap on gcc 11 (C++20): https://github.com/mirror/tclap/issues/7
Fix: https://github.com/ufz/tclap/commit/098dd0fe07a31618f3c2a9f8727bb01c8c5d61e2
Fixes compilation issue with tclap on gcc 11 (C++20): https://github.com/mirror/tclap/issues/7
Fix: https://github.com/ufz/tclap/commit/098dd0fe07a31618f3c2a9f8727bb01c8c5d61e2