Replace unmaintained structopt with clap (#73)

Use `clap` and `clap_derive` to replace the functionality of `structopt`
which is unmaintained.

This also bumps the rust toolchain to `1.74`.

Author: emanueleaina

.github/workflows/ci.yml

@@ -18,7 +18,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@master # avoid the tag here to prevent dependabot from updating it
         with:
-            toolchain: "1.73"
+            toolchain: "1.74"
       - run: cargo check --all-targets --all-features
 
   fmt:
@@ -28,7 +28,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@master # avoid the tag here to prevent dependabot from updating it
         with:
-            toolchain: "1.73"
+            toolchain: "1.74"
             components: rustfmt
       - run: cargo fmt --all --check
 
@@ -39,7 +39,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@master # avoid the tag here to prevent dependabot from updating it
         with:
-            toolchain: "1.73"
+            toolchain: "1.74"
       - run: cargo test --all-targets --all-features
       - run: cargo test --doc
 
@@ -50,7 +50,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@master # avoid the tag here to prevent dependabot from updating it
         with:
-            toolchain: "1.73"
+            toolchain: "1.74"
             components: clippy
       - run: cargo clippy --all-targets --all-features -- -D warnings