switch to the latest rust toolchain

stlankes · stlankes · commit b02a7ab94b49 · 2021-05-20T12:59:41.000+02:00
diff --git a/rust-toolchain b/rust-toolchain
@@ -1,3 +1,3 @@
 [toolchain]
-channel = "nightly-2021-05-11"
+channel = "nightly-2021-05-19"
 components = [ "rustfmt", "rust-src", "llvm-tools-preview"]
