Set sponsorship hash to upper

CHANGELOG:

### ADDED
- [#821](https://gitlab.com/coopdevs/odoo-somconnexio/-/merge_requests/821) Set sponsorship hash to upper

Related card: https://trello.com/c/Xxa7wL54/1281-codi-dapadrinament-generar-el-codi-sempre-en-maj%C3%BAscules

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