chore: Update rust-toolchain to 1.66 for testing (#208)

* chore: Update rust-toolchain to 1.66 for testing

Note that tests will not compile due to the silent MSRV bump in
`blake2b_simd`.

Hence, we need to use `1.66` as toolchain.

Resolves: #207

* change: UIpdate MSRVs in Cargo.toml

halo2_gadgets/Cargo.toml

@@ -9,7 +9,7 @@ authors = [
     "Kris Nuttycombe <kris@electriccoin.co>",
 ]
 edition = "2021"
-rust-version = "1.56.1"
+rust-version = "1.66.0"
 description = "Reusable gadgets and chip implementations for Halo 2"
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/zcash/halo2"
@@ -32,7 +32,7 @@ halo2curves = { version = "0.1.0" }
 proptest = { version = "1.0.0", optional = true }
 rand = "0.8"
 subtle = "2.3"
-uint = "0.9.2" # MSRV 1.56.1
+uint = "0.9.2" 
 
 # Developer tooling dependencies
 plotters = { version = "0.3.0", default-features = false, optional = true }

halo2_proofs/Cargo.toml

@@ -8,7 +8,7 @@ authors = [
     "Jack Grigg <jack@electriccoin.co>",
 ]
 edition = "2021"
-rust-version = "1.56.1"
+rust-version = "1.66.0"
 description = """
 Fast PLONK-based zero-knowledge proving system with no trusted setup
 """
@@ -54,7 +54,7 @@ group = "0.13"
 halo2curves = { version = "0.1.0" }
 rand_core = { version = "0.6", default-features = false }
 tracing = "0.1"
-blake2b_simd = "1"
+blake2b_simd = "1" # MSRV 1.66.0
 sha3 = "0.9.1"
 rand_chacha = "0.3"
 maybe-rayon = { version = "0.1.0", default-features = false }

rust-toolchain

@@ -1 +1 @@
-1.65.0
+1.66.0