Prepare the 1.20.0 beta release

This commit prepares the freshly branched `beta` branch to start bootstrapping
from the 1.19.0 preview artifacts as well as build in beta mode.

Author: alexcrichton

src/ci/run.sh

@@ -44,7 +44,7 @@ fi
 # FIXME: need a scheme for changing this `nightly` value to `beta` and `stable`
 #        either automatically or manually.
 if [ "$DEPLOY$DEPLOY_ALT" != "" ]; then
-  RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --release-channel=nightly"
+  RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --release-channel=beta"
   RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --enable-llvm-static-stdcpp"
 
   if [ "$NO_LLVM_ASSERTIONS" = "1" ]; then

src/stage0.txt

@@ -12,9 +12,9 @@
 # source tarball for a stable release you'll likely see `1.x.0` for rustc and
 # `0.x.0` for Cargo where they were released on `date`.
 
-date: 2017-06-15
-rustc: beta
-cargo: beta
+date: 2017-07-18
+rustc: 1.19.0
+cargo: 0.20.0
 
 # When making a stable release the process currently looks like:
 #
@@ -34,4 +34,4 @@ cargo: beta
 # looking at a beta source tarball and it's uncommented we'll shortly comment it
 # out.
 
-#dev: 1
+dev: 1