build: Bump MSRV to 1.82.0

We are having complains from Rust 1.86.0-beta.1 (f0cb41030 2025-02-17)'
clippy, which suggests us to replace `repeat().take()` with
`repeat_n()`. While `repeat_n()` is stablized in Rust 1.82.0.

Update image to 20250307-2 because MSRV in Dockerfile is updated.

Signed-off-by: Rob Bradford <rbradford@rivosinc.com>
Signed-off-by: Ruoqing He <heruoqing@iscas.ac.cn>

Cargo.toml

@@ -15,7 +15,7 @@ version = "44.0.0"
 # a.) A dependency requires it,
 # b.) If we want to use a new feature and that MSRV is at least 6 months old,
 # c.) There is a security issue that is addressed by the toolchain update.
-rust-version = "1.77.0"
+rust-version = "1.82.0"
 
 [profile.release]
 codegen-units = 1