Whenever a dependency from a git repository is specified without any other specifiers (namely via the properties rev, tag, or branch), that means that it is specified to the latest revision of the main branch of that repository. But in any case, updating any dependency requires updating the project's Cargo.lock file. This generally means using the cargo update command.

cargo update

This will also detect any changes to the version or origin requirements and update the dependency lock accordingly.

I tried to use this command: cargo install rust_wheel --force

That is the wrong Cargo command. cargo install is for installing binaries to the system, not to install dependencies. This is well documented too.

Also tried cargo update rust_wheel.

Wrong syntax. To issue an update of a specific dependency, use the -p option.

cargo update -p rust_wheel

See also:

• The Rust reference on Cargo Commands

This is possible without Cargo, but you'll have to do what it normally does for you.

1. Download all the dependencies.
2. Compile all the dependencies with rustc using the correct flags.

rand v0.7.3
├── getrandom v0.1.14
│   ├── cfg-if v0.1.10
│   └── libc v0.2.66
├── libc v0.2.66 (*)
├── rand_chacha v0.2.1
│   ├── c2-chacha v0.2.3
│   │   └── ppv-lite86 v0.2.6
│   └── rand_core v0.5.1
│       └── getrandom v0.1.14 (*)
└── rand_core v0.5.1 (*)

rand isn't too bad, with only 8 transitive dependencies (including rand itself, not including duplicates). Still, you'll have to go to crates.io or github and download the correct version of the source for each.

Then comes compiling. The minimum you'll have to do to compile your own binary is rustc -L dependency=/path/to/dependency/dir src/main.rs. But remember that you have to do this for each of the 8 dependencies, and all of those have their own external dependencies. You'll also need to figure out the right order to compile them.

Moveover, some crates have their own settings in their Cargo.toml that have to be respected. Some crates even have a build script that needs to be compiled and run (libc is an example in this dependency tree).

Alternatively, you could just put

[dependencies]
rand = "0.7.3"

in your Cargo.toml and run cargo build. Your choice. Cargo is one of the nicest things about Rust, so I suggest you use it.

P.S. To see what exactly cargo is doing, run cargo clean to remove any already compiled dependencies. Then run cargo build --verbose (or cargo build -vv if you're brave). You'll see all the flags that get passed to rustc, scripts that get run and everything else.