Rollup merge of rust-lang#73411 - ehuss:bump-stage0, r=Mark-Simulacrum

Update bootstrap to rustc 1.45.0-beta.2 (1dc0f6d 2020-06-15)

Pulls in changes from rust-lang#73326.

Closes rust-lang#73286

Author: Manishearth

src/stage0.txt

@@ -12,7 +12,7 @@
 # source tarball for a stable release you'll likely see `1.x.0` for rustc and
 # `0.(x+1).0` for Cargo where they were released on `date`.
 
-date: 2020-06-03
+date: 2020-06-16
 rustc: beta
 cargo: beta