CI: Run clang-tidy on dpcpp:ubuntu22.04-latest

We haven't built hipsycl:ubuntu22.04-latest in a while; this just worked
by accident.

Author: psalz

.github/workflows/celerity_ci.yml

@@ -58,7 +58,7 @@ jobs:
     container:
       # We could run this for more than one implementation,
       # but would likely end up with mostly duplicate diagnostics.
-      image: ghcr.io/celerity/celerity-build/hipsycl:ubuntu22.04-latest
+      image: ghcr.io/celerity/celerity-build/dpcpp:ubuntu22.04-latest
       volumes:
         - ccache:/ccache
       credentials: