Add clippy.toml

Explicitly sets the project MSRV so that clippy won't give warnings
for feature added after our MSRV

diff --git a/clippy.toml b/clippy.toml
new file mode 100644 (file)
index 0000000..3f726db
--- /dev/null
+++ b/clippy.toml
@@ -0,0 +1 @@
+msrv="1.57.0"