message: Use rev instead of pointing to a branch
diff: @@ -14,6 +14,6 @@ forest_address = "0.2.0"
  forest_encoding = "0.1.1"
  forest_cid = "0.1.0"
  num_bigint = { package = "forest_bigint", version = "0.1.0"}
  -clock = { git = "https://github.com/chainsafe/forest", branch="main" }
  +clock = { git = "https://github.com/chainsafe/forest", rev="2863f64e40fde88433f9a00be764872f54c2e5ba" }
  serde = { version = "1.0", features = ["derive"] }
  lazy_static = "1.4.0"
  