Downgrade toolchain to avoid a rust-analyzer bug

jeromerobert · jeromerobert · commit 09300225740c · 2022-07-13T17:07:09.000+02:00
rust-lang/rust-analyzer#12600
diff --git a/rust-toolchain.toml b/rust-toolchain.toml
@@ -1,2 +1,2 @@
 [toolchain]
-channel = "nightly-2022-06-21"
+channel = "nightly-2022-06-18"
