ci: don't store $CARGO_HOME in Github Actions cache (denoland#9779)

There currently is a problem related to Github Actions in general or the
'actions-rs/cargo' action in particular, which causes cargo to be unable
to find the 'serde_derive' crate when the cargo home dir has been
restored from cache.

This issue is also being reported by others, e.g. at
actions-rs/cargo#111.

Author: ry

.github/workflows/ci.yml

@@ -89,7 +89,6 @@ jobs:
           path: |
             ~/.cargo/registry
             ~/.cargo/git
-            .cargo_home
             target/*/.*
             target/*/build
             target/*/deps