Mock server returns int64 value less than the lower limit

[atkei]

Describe the bug

The range of int64 is -9223372036854775808 (-2^63) ~ 9223372036854775807 (2^63-1), but the mock server seems to return -9223372036854776000 by default.

To Reproduce

1. Install prism.

npm install -g @stoplight/prism-cli

2. Start a mock server with the following command.

prism mock https://raw.githack.com/OAI/OpenAPI-Specification/master/examples/v3.0/petstore-expanded.yaml

3. Call a REST API that returns a response containing an int64 value.

curl -X GET "http://localhost:4010/pets/1"
{"name":"string","tag":"string","id":-9223372036854776000}

Expected behavior

The mock server returns -9223372036854775808 or a value in the range of int64.

Additional context

Environment (remove any that are not applicable):

• Library version: 4.7.0
• OS: Pop!_OS 21.04
• Browser: Not using
• Platform: Desktop