Temporarily disable miri CI

rust-lang/miri#2874

Author: dtolnay

.github/workflows/ci.yml

@@ -152,6 +152,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: dtolnay/rust-toolchain@miri
       - run: cargo miri test --all-features
+        continue-on-error: true # https://github.com/rust-lang/miri/issues/2874
         env:
           MIRIFLAGS: -Zmiri-strict-provenance