Upgrade to Rust 1.87 (#7346)

I ignored some new clippy lints about large differences between enum variants.
We can always revisit these later (the compiler suggests boxing them so
that the enum variants are similar size)

rust/kcl-lib/src/execution/exec_ast.rs

@@ -1351,7 +1351,7 @@ pub(crate) async fn execute_pipe_body(
     // Now that we've evaluated the first child expression in the pipeline, following child expressions
     // should use the previous child expression for %.
     // This means there's no more need for the previous pipe_value from the parent AST node above this one.
-    let previous_pipe_value = std::mem::replace(&mut exec_state.mod_local.pipe_value, Some(output));
+    let previous_pipe_value = exec_state.mod_local.pipe_value.replace(output);
     // Evaluate remaining elements.
     let result = inner_execute_pipe_body(exec_state, body, ctx).await;
     // Restore the previous pipe value.