ci: test MSRV and minimal versions; also fix thiserror min version

.github/workflows/main.yml

@@ -24,6 +24,20 @@ jobs:
         with:
           command: build
 
+  build_msrv:
+    name: build with MSRV (1.66.1)
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4.1.1
+      # Re-resolve Cargo.lock with minimal versions
+      - uses: dtolnay/rust-toolchain@nightly
+      - run: cargo update -Z minimal-versions
+      # Now check that `cargo build` works with respect to the oldest possible
+      # deps and the stated MSRV
+      - uses: dtolnay/rust-toolchain@1.66.1
+      - run: cargo build --all-features
+
   test_beta:
     name: test on beta
     runs-on: ubuntu-latest

frost-core/Cargo.toml

@@ -32,7 +32,7 @@ postcard = { version = "1.0.0", features = ["use-std"], optional = true }
 rand_core = "0.6"
 serde = { version = "1.0.160", features = ["derive"], optional = true }
 serdect = { version = "0.2.0", optional = true }
-thiserror = "1.0"
+thiserror = "1.0.29"
 visibility = "0.1.0"
 zeroize = { version = "1.5.4", default-features = false, features = ["derive"] }
 itertools = "0.12.0"