add josh-sync configuration and CI

Author: makai410

.github/workflows/rustc_pull.yml

@@ -0,0 +1,18 @@
+name: rustc-pull
+
+on:
+  workflow_dispatch:
+  schedule:
+    # Run at 04:00 UTC every day
+    - cron: "0 4 * * *"
+
+jobs:
+  pull:
+    if: github.repository == 'rust-lang/project-stable-mir'
+    uses: rust-lang/josh-sync/.github/workflows/rustc-pull.yml@main
+    with:
+      github-app-id: ${{ vars.APP_CLIENT_ID }}
+      pr-base-branch: main
+      branch-name: rustc-pull
+    secrets:
+      github-app-secret: ${{ secrets.APP_PRIVATE_KEY }}

josh-sync.toml

@@ -0,0 +1,3 @@
+org = "rust-lang"
+repo = "project-stable-mir"
+filter = ":/compiler/rustc_public:prefix=rustc_public"

rust-version

@@ -0,0 +1 @@
+bec747418c9955de4c3fd0aac4acb99206f00aa2