[bug]: Invalid value in the `X-Protobuf-Schema` HTTP header

[petrkutalek]

The X-Protobuf-Schema HTTP header returned in the /api/v1 calls (like GET /api/v1/fromradio, PUT /api/v1/toradio etc.) is invalid.

Meshtastic returns URL which does not exist (anymore?):

X-Protobuf-Schema: https://raw.githubusercontent.com/meshtastic/protobufs/master/mesh.proto

The correct one is

X-Protobuf-Schema: https://raw.githubusercontent.com/meshtastic/protobufs/master/meshtastic/mesh.proto