Update toml dependency to latest version

I am in the process of vendoring UniFFI in AOSP, which means that I
have to make it play nice with the existing crates found here:

  https://cs.android.com/android/platform/superproject/+/main:external/rust/crates/

Android tries to only vendor each crate in a single version, so it
would be helpful for me if the toml dependency could be updated.

uniffi_bindgen/Cargo.toml

@@ -23,7 +23,7 @@ heck = "0.4"
 once_cell = "1.12"
 paste = "1.0"
 serde = { version = "1", features = ["derive"] }
-toml = "0.5"
+toml = "0.8"
 uniffi_meta = { path = "../uniffi_meta", version = "=0.26.1" }
 uniffi_testing = { path = "../uniffi_testing", version = "=0.26.1" }
 uniffi_udl = { path = "../uniffi_udl", version = "=0.26.1" }

uniffi_bindgen/src/lib.rs

@@ -354,8 +354,9 @@ fn crate_name_from_cargo_toml(udl_file: &Utf8Path) -> Result<String> {
     let file = guess_crate_root(udl_file)?.join("Cargo.toml");
     let cargo_toml_bytes =
         fs::read(file).context("Can't find Cargo.toml to determine the crate name")?;
-
-    let cargo_toml = toml::from_slice::<CargoToml>(&cargo_toml_bytes)?;
+    let cargo_toml_string =
+        String::from_utf8(cargo_toml_bytes).context("Could not UTF-8 decode Cargo.toml")?;
+    let cargo_toml = toml::from_str::<CargoToml>(&cargo_toml_string)?;
 
     let lib_crate_name = cargo_toml
         .lib

uniffi_macros/Cargo.toml

@@ -23,7 +23,7 @@ proc-macro2 = "1.0"
 quote = "1.0"
 serde = { version = "1.0.136", features = ["derive"] }
 syn = { version = "2.0", features = ["full", "visit-mut"] }
-toml = "0.5.9"
+toml = "0.8"
 uniffi_build = { path = "../uniffi_build", version = "=0.26.1", optional = true }
 uniffi_meta = { path = "../uniffi_meta", version = "=0.26.1" }
 

uniffi_macros/src/util.rs

@@ -46,8 +46,9 @@ pub fn mod_path() -> syn::Result<String> {
     static LIB_CRATE_MOD_PATH: Lazy<Result<String, String>> = Lazy::new(|| {
         let file = manifest_path()?;
         let cargo_toml_bytes = fs::read(file).map_err(|e| e.to_string())?;
-
-        let cargo_toml = toml::from_slice::<CargoToml>(&cargo_toml_bytes)
+        let cargo_toml_string = String::from_utf8(cargo_toml_bytes)
+            .map_err(|e| format!("Could not UTF-8 decode `Cargo.toml`: {e}"))?;
+        let cargo_toml = toml::from_str::<CargoToml>(&cargo_toml_string)
             .map_err(|e| format!("Failed to parse `Cargo.toml`: {e}"))?;
 
         let lib_crate_name = cargo_toml