schemas: byte and uintDecimal patterns fixed to match geth

[felix314159]

two regex patterns in src/schemas/base-types.yaml diverge from what geth actually does:

• byte

- ^0x([0-9a-fA-F]?){1,2}$
+ ^0x[0-9a-f]{1,2}$

Old pattern allows "0x" but geth would always append at least one hex digit (e.g. to make it 0x0 in the smallest case)

---

• uintDecimal

- ^[1-9][0-9]*$
+ ^(0|[1-9][0-9]*)$

old pattern rejects "0" but geth allows plain 0 (here api.networkVersion is just uint64 and there is no guarding or whatever against 0). i used this example cuz it is the JSON-emitter for net_version

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AFAIK all in-spec example values that resolve to these two types still validate without additional changes