docs(readme): update MSRV in README.md (#92)

Update MSRV to satisfy the following features:

- `is_sorted`: stable at `1.82.0`
- `is_some_and`: stable at `1.70.0`
- `&mut in const`: stable at `1.83.0`

Signed-off-by: Nuoxian Wang <bosswnx@qq.com>

README.md

@@ -20,7 +20,7 @@ or consult vendors if they provide discrete RustSBI package support.
 
 ## Minimum supported Rust version
 
-To compile RustSBI library, you need at least stable Rust version of `rustc 1.65.0`.
+To compile RustSBI library, you need at least stable Rust version of `rustc 1.83.0`.
 
 ## Build this project