Omit --tests argument from cargo clippy CI job

The --all-targets argument that we provide to the cargo clippy
invocation already captures all targets. As such, there is no reason to
specify --tests as well. Remove this argument.

.github/workflows/test.yml

@@ -1,4 +1,4 @@
-# Copyright (C) 2022-2023 Daniel Mueller <deso@posteo.net>
+# Copyright (C) 2022-2024 Daniel Mueller <deso@posteo.net>
 # SPDX-License-Identifier: GPL-3.0-or-later
 
 name: Test
@@ -64,7 +64,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: dtolnay/rust-toolchain@stable
       - uses: Swatinem/rust-cache@v2
-      - run: cargo clippy --no-deps --all-targets --all-features --tests -- -A unknown_lints -A deprecated -D warnings
+      - run: cargo clippy --no-deps --all-targets --all-features -- -A unknown_lints -A deprecated -D warnings
   rustfmt:
     name: Check code formatting
     runs-on: ubuntu-latest