chore(deps): bump dtolnay/rust-toolchain from 1.81 to 1.90

Bumps [dtolnay/rust-toolchain](https://github.com/dtolnay/rust-toolchain) from 1.81 to 1.90.
- [Release notes](https://github.com/dtolnay/rust-toolchain/releases)
- [Commits](dtolnay/rust-toolchain@1.81...1.90)

---
updated-dependencies:
- dependency-name: dtolnay/rust-toolchain
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/ci.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@1.81
+      - uses: dtolnay/rust-toolchain@1.90
       - run: cargo test --all-targets --all-features
       - run: cargo test --doc --all-features
 
@@ -21,7 +21,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@1.81
+      - uses: dtolnay/rust-toolchain@1.90
         with:
             components: rustfmt
       - run: cargo fmt --all --check
@@ -31,7 +31,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@1.81
+      - uses: dtolnay/rust-toolchain@1.90
         with:
             components: clippy
       - run: cargo clippy --all-targets --all-features -- -D warnings