Bump MSRV to 1.75

```
  error[E0015]: cannot call non-const fn `zeroed::<sem_t>` in statics
    --> /home/runner/.cargo/registry/src/index.crates.io-6f17d22bba15001f/ctrlc-3.5.0/src/platform/unix/mod.rs:15:55
     |
  15 |     static mut SEMAPHORE: nix::libc::sem_t = unsafe { std::mem::zeroed() };
     |                                                       ^^^^^^^^^^^^^^^^^^
     |
     = note: calls in statics are limited to constant functions, tuple structs and tuple variants
     = note: consider wrapping this expression in `Lazy::new(|| ...)` from the `once_cell` crate: https://crates.io/crates/once_cell
```

Author: taiki-e

Cargo.toml

@@ -2,7 +2,8 @@
 name = "cargo-hack"
 version = "0.6.37" #publish:version
 edition = "2021"
-rust-version = "1.71" # For cargo-config2
+# NB: Sync with the MSRV in "From source" section in README.md.
+rust-version = "1.75" # For ctrlc
 license = "Apache-2.0 OR MIT"
 repository = "https://github.com/taiki-e/cargo-hack"
 keywords = ["cargo", "subcommand", "testing"]

README.md

@@ -469,7 +469,7 @@ fields of [`cargo metadata`][cargo-metadata].*
 cargo +stable install cargo-hack --locked
 ```
 
-Currently, installing cargo-hack requires rustc 1.71+.
+Currently, installing cargo-hack requires rustc 1.75+.
 
 cargo-hack is usually runnable with Cargo versions older than the Rust version
 required for installation (e.g., `cargo +1.31 hack check`). Currently, to run

src/main.rs

@@ -167,12 +167,7 @@ struct Progress {
 
 impl Progress {
     fn in_partition(&self, partition: &Partition) -> bool {
-        // div_ceil requires Rust 1.73
-        let mut chunk_count = self.total / partition.count;
-        if self.total % partition.count != 0 {
-            chunk_count += 1;
-        }
-        let current_index = self.count / chunk_count;
+        let current_index = self.count / self.total.div_ceil(partition.count);
         current_index == partition.index
     }
 }