Add test for publish = true.

tests/ui-cargo/cargo_common_metadata/fail_publish_true/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "cargo_common_metadata"
+version = "0.1.0"
+publish = true
+
+[workspace]

tests/ui-cargo/cargo_common_metadata/fail_publish_true/src/main.rs

@@ -0,0 +1,4 @@
+// compile-flags: --crate-name=cargo_common_metadata
+#![warn(clippy::cargo_common_metadata)]
+
+fn main() {}

tests/ui-cargo/cargo_common_metadata/fail_publish_true/src/main.stderr

@@ -0,0 +1,18 @@
+error: package `cargo_common_metadata` is missing `package.authors` metadata
+   |
+   = note: `-D clippy::cargo-common-metadata` implied by `-D warnings`
+
+error: package `cargo_common_metadata` is missing `package.description` metadata
+
+error: package `cargo_common_metadata` is missing `either package.license or package.license_file` metadata
+
+error: package `cargo_common_metadata` is missing `package.repository` metadata
+
+error: package `cargo_common_metadata` is missing `package.readme` metadata
+
+error: package `cargo_common_metadata` is missing `package.keywords` metadata
+
+error: package `cargo_common_metadata` is missing `package.categories` metadata
+
+error: aborting due to 7 previous errors
+