build(Justfile): add release binaries

Refs: #101
Signed-off-by: Christina Sørensen <christina@cafkafk.com>

Justfile

@@ -135,3 +135,15 @@ alias itest := integration_tests
     echo "waiting 10 seconds for github to catch up..."
     sleep 10
     gh pr create --draft --title "chore: release $(grep '^version' Cargo.toml | head -n 1 | grep -E '([0-9]+)\.([0-9]+)\.([0-9]+)(?:-([0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*))?(?:\+[0-9A-Za-z-]+)?' -o)" --body "This PR was auto-generated by our lovely just file" --reviewer cafkafk 
+
+# If you're not cafkafk and she isn't dead, you probably don't need to run
+# this!
+# 
+# usage: cross
+@cross: 
+    rustup toolchain install stable
+    cross build --target x86_64-unknown-linux-gnu
+    cross build --target aarch64-unknown-linux-gnu
+    cross build --target aarch64-apple-darwin
+    cross build --target x86_64-pc-windows-gnu
+    cross build --target aarch64-pc-windows-gnullvm

flake.nix

@@ -148,7 +148,7 @@
 
         # For `nix develop`:
         devShells.default = pkgs.mkShell {
-          nativeBuildInputs = with pkgs; [toolchain just pandoc packages.vhs convco];
+          nativeBuildInputs = with pkgs; [rustup toolchain just pandoc packages.vhs convco];
         };
 
         # For `nix flake check`