update: use sample interval default 1000

[RafaelGSS]

This PR is causing unexpected behavior in some measurements:

fastify/benchmarks#233 and I believe for most of the users is better to use default as 1000 at least is more readable than:

│ Stat      │ 1%      │ 2.5%    │ 50%     │ 97.5%   │ Avg     │ Stdev   │ Min   │
├───────────┼─────────┼─────────┼─────────┼─────────┼─────────┼─────────┼───────┤
│ Req/Sec   │ 16      │ 32      │ 55      │ 89      │ 54.75   │ 11.09   │ 1     │
├───────────┼─────────┼─────────┼─────────┼─────────┼─────────┼─────────┼───────┤
│ Bytes/Sec │ 2.99 kB │ 5.99 kB │ 10.3 kB │ 16.7 kB │ 10.2 kB │ 2.07 kB │ 187 B │
└───────────┴─────────┴─────────┴─────────┴─────────┴─────────┴─────────┴───────┘

Req/Bytes counts sampled every 0.001 seconds.

[mcollina]

lgtm

[RafaelGSS]

@mcollina can you re-run all jobs, please? I don't have this permission

[mcollina]

lgtm