add rust toolchain file to pin rust version (#6298)

* add rust toolchain file to pin rust version

* rust 1.63 release, bump toolchain

* linux clippy

* pin to 1.63

* pin to 1.61

crates/nu-table/src/table.rs

@@ -298,7 +298,7 @@ impl TableOption for FooterStyle {
             return;
         }
 
-        if let Some(line) = grid.get_split_line(1) {
+        if let Some(line) = grid.clone().get_split_line(1) {
             grid.set_split_line(grid.count_rows() - 1, line.clone());
         }
     }

rust-toolchain.toml

@@ -0,0 +1,19 @@
+# So, you want to update the Rust toolchain...
+# The key is making sure all our dependencies support the version of Rust we're using,
+# and that nushell compiles on all the platforms tested in our CI.
+
+# Here's some documentation on how to use this file:
+# https://rust-lang.github.io/rustup/overrides.html#the-toolchain-file
+
+[toolchain]
+# The default profile includes rustc, rust-std, cargo, rust-docs, rustfmt and clippy.
+# https://rust-lang.github.io/rustup/concepts/profiles.html
+profile = "default"
+# The current plan is to be 2 releases behind the latest stable release. So, if the
+# latest stable release is 1.62.0, the channel should be 1.60.0. We want to do this
+# so that we give repo maintainers and package managers a chance to update to a more
+# recent version of rust. However, if there is a "cool new feature" that we want to
+# use in nushell, we may opt to use the bleeding edge stable version of rust.
+# I believe rust is on a 6 week release cycle and nushell is on a 3 week release cycle.
+# So, every two nushell releases, this version number should be bumped by one.
+channel = "1.61.0"