Bump nightly version -> 2021-06-03

flip1995 · flip1995 · commit ab8bede9d7fe · 2021-06-03T08:38:19.000+02:00
diff --git a/rust-toolchain b/rust-toolchain
@@ -1,3 +1,3 @@
 [toolchain]
-channel = "nightly-2021-05-20"
+channel = "nightly-2021-06-03"
 components = ["llvm-tools-preview", "rustc-dev", "rust-src"]
