[`Arm::ethos-u-core-driver`] Pack vendor name inconsistency

[brondani]

Among the packs listed in the index.pidx all other ARM packs have capitalized vendor name, being Arm::ethos-u-core-driver the only one with different letter case.
Being the vendor name part of the mandatory pack repository structure, the packs will be installed in different folders depending on the file system's letter case sensitiveness and, when case insensitive, on what directory has been created first.

This can lead to portability issues:

• makes the pack selection prone to misspelling, which can be tollerated in case insensitive systems but not otherwise.
• hinders the pack repository sharing.

Side note: a stricter case check for ensuring portability, introduced in toolbox 2.7.0, has proved to be too disruptive due to this pack name inconsistency: Open-CMSIS-Pack/cmsis-toolbox#269