xml and upf templates for Y and Nb are missing.

[Hyeondeok-Shin]

In the library, Y and Nb support other templates, but they don't have xml and upf format which require for QMCPACK and Quantum Espresso.

[aannabe]

Y and Nb ccECP upf files were not included since there were significant difficulties with ghost states in the generation. There should not be any issues with generating xml files though. Ultimately, the plan was to create softer versions of Y and Nb and include both upf and xml files for them. I am unsure about the status of these new versions of Y and Nb.