Update CI workflow

Author: Kobzol

.github/workflows/ci.yml

@@ -147,16 +147,16 @@ jobs:
       - uses: actions/checkout@v4
         with:
           fetch-depth: 256 # get a bit more of the history
-      - name: install josh-proxy
-        run: cargo +stable install josh-proxy --git https://github.com/josh-project/josh --tag r24.10.04
+      - name: install josh-sync
+        run: cargo +stable install --locked --git https://github.com/rust-lang/josh-sync
       - name: setup bot git name and email
         run: |
           git config --global user.name 'The Miri Cronjob Bot'
           git config --global user.email 'miri@cron.bot'
       - name: Install nightly toolchain
         run: rustup toolchain install nightly --profile minimal
       - name: get changes from rustc
-        run: ./miri rustc-pull
+        run: rustc-josh-sync pull --allow-noop
       - name: Install rustup-toolchain-install-master
         run: cargo install -f rustup-toolchain-install-master
       - name: format changes (if any)
@@ -166,7 +166,7 @@ jobs:
       - name: Push changes to a branch and create PR
         run: |
           # `git diff --exit-code` "succeeds" if the diff is empty.
-          if git diff --exit-code HEAD^; then echo "Nothing changed in rustc, skipping PR"; exit 0; fi
+          if git diff --exit-code ${GITHUB_SHA}; then echo "Nothing changed in rustc, skipping PR"; exit 0; fi
           # The diff is non-empty, create a PR.
           BRANCH="rustup-$(date -u +%Y-%m-%d)"
           git switch -c $BRANCH