chore: improve MSRV to 1.87

Signed-off-by: Haobo Gu <haobogu@outlook.com>

Cargo.toml

@@ -2,7 +2,7 @@
 name = "smoltcp"
 version = "0.12.0"
 edition = "2021"
-rust-version = "1.81"
+rust-version = "1.87"
 authors = ["whitequark <whitequark@whitequark.org>"]
 description = "A TCP/IP stack designed for bare-metal, real-time systems without a heap."
 documentation = "https://docs.rs/smoltcp/"

README.md

@@ -12,7 +12,7 @@ include complicated compile-time computations, such as macro or type tricks, eve
 at cost of performance degradation.
 
 _smoltcp_ does not need heap allocation *at all*, is [extensively documented][docs],
-and compiles on stable Rust 1.81 and later.
+and compiles on stable Rust 1.87 and later.
 
 _smoltcp_ achieves [~Gbps of throughput](#examplesbenchmarkrs) when tested against
 the Linux TCP stack in loopback mode.

ci.sh

@@ -4,7 +4,7 @@ set -eox pipefail
 
 export DEFMT_LOG=trace
 
-MSRV="1.81.0"
+MSRV="1.87.0"
 
 RUSTC_VERSIONS=(
     $MSRV

src/lib.rs

@@ -65,7 +65,7 @@
 //!
 //! # Minimum Supported Rust Version (MSRV)
 //!
-//! This crate is guaranteed to compile on stable Rust 1.81 and up with any valid set of features.
+//! This crate is guaranteed to compile on stable Rust 1.87 and up with any valid set of features.
 //! It *might* compile on older versions but that may change in any new patch release.
 //!
 //! The exception is when using the `defmt` feature, in which case `defmt`'s MSRV applies, which