Correctly add Cargo.lock to sdsit (#13909)

changelog.d/13909.bugfix

@@ -0,0 +1 @@
+Fix packaging to include `Cargo.lock` in `sdist`.

pyproject.toml

@@ -86,8 +86,8 @@ include = [
     { path = "tests", format = "sdist" },
     { path = "UPGRADE.rst", format = "sdist" },
     { path = "Cargo.toml", format = "sdist" },
+    { path = "Cargo.lock", format = "sdist" },
     { path = "rust/Cargo.toml", format = "sdist" },
-    { path = "rust/Cargo.lock", format = "sdist" },
     { path = "rust/build.rs", format = "sdist" },
     { path = "rust/src/**", format = "sdist" },
 ]