Adding Petersburg and Constantinople fork blocks

Author: evertonfraga

src/chains/rinkeby.json

@@ -52,7 +52,13 @@
  },
  {
  "name": "constantinople",
- "block": null,
+ "block": 3660663,
+ "consensus": "poa",
+ "finality": null
+ },
+ {
+ "name": "petersburg",
+ "block": 9999999,
  "consensus": "poa",
  "finality": null
  },