chore: disable some unused default features (#117)

# Rationale for this change

To build this crate for `wasm32-unknown-unknown` to run on runtimes with
a limited custom API available (e.g., Linera contracts), `wasm-bindgen`
should not be a dependency. That's because `wasm-bindgen` generates
bindings for the Javascript APIs available in browsers (and similar
runtimes). For more bare-bones runtimes, these APIs aren't available.

# What changes are included in this PR?

Disabling the `default` features of `chrono`, `rand` and `rand-core`.

Unfortunately, this doesn't complete the work to support
`wasm32-unknown-unknown` without JS, because a fix is also needed in
`merlin` (zkcrypto/merlin#8).

# Are these changes tested?

Tested with `cargo test`.

Cargo.toml

@@ -29,7 +29,7 @@ bytemuck = {version = "1.16.3", features = ["derive"]}
 byte-slice-cast = { version = "1.2.1" }
 clap = { version = "4.5.4" }
 criterion = { version = "0.5.1" }
-chrono = { version = "0.4.38" }
+chrono = { version = "0.4.38", default-features = false }
 curve25519-dalek = { version = "4", features = ["rand_core"] }
 derive_more = { version = "0.99" }
 flexbuffers = { version = "2.0.0" }
@@ -45,8 +45,8 @@ opentelemetry-jaeger = { version = "0.20.0" }
 postcard = { version = "1.0" }
 proof-of-sql = { path = "crates/proof-of-sql" } # We automatically update this line during release. So do not modify it!
 proof-of-sql-parser = { path = "crates/proof-of-sql-parser" } # We automatically update this line during release. So do not modify it!
-rand = { version = "0.8" }
-rand_core = { version = "0.6" }
+rand = { version = "0.8", default-features = false }
+rand_core = { version = "0.6", default-features = false }
 rayon = { version = "1.5" }
 serde = { version = "1" }
 serde_json = { version = "1" }

crates/proof-of-sql/Cargo.toml

@@ -30,7 +30,7 @@ bumpalo = { workspace = true, features = ["collections"] }
 bytemuck = { workspace = true }
 byte-slice-cast = { workspace = true }
 curve25519-dalek = { workspace = true, features = ["serde"] }
-chrono = {workspace = true, features = ["serde"]}
+chrono = { workspace = true, features = ["serde"] }
 derive_more = { workspace = true }
 indexmap = { workspace = true, features = ["serde"] }
 itertools = { workspace = true }
@@ -40,7 +40,7 @@ num-traits = { workspace = true }
 num-bigint = { workspace = true, default-features = false }
 postcard = { workspace = true, features = ["alloc"] }
 proof-of-sql-parser = { workspace = true }
-rand = { workspace = true, optional = true }
+rand = { workspace = true, default-features = false, optional = true }
 rayon = { workspace = true }
 serde = { workspace = true, features = ["serde_derive"] }
 serde_json = { workspace = true }
@@ -55,8 +55,8 @@ clap = { workspace = true, features = ["derive"] }
 criterion = { workspace = true, features = ["html_reports"] }
 opentelemetry = { workspace = true }
 opentelemetry-jaeger = { workspace = true }
-rand = { workspace = true }
-rand_core = { workspace = true }
+rand = { workspace = true, default-features = false }
+rand_core = { workspace = true, default-features = false }
 serde_json = { workspace = true }
 tracing = { workspace = true }
 tracing-opentelemetry = { workspace = true }