chore: address cargo-semver-checks run time

This PR improves the `semver-checks` CI job by introducing caching to speed up executions and removing the explicit `cargo semver-checks` invocation, as it is already handled by the action by default.

The initial run with a cold cache is expected to take approximately 23 minutes, which is unchanged from the current execution time as the cache is being populated,  subsequent runs with a warm cache are expected to complete in approximately 3–6 minutes which reduces the job execution time by approximately 74–87% for cached runs.

Pull-Request: #6437.

Author: jduarte

.github/workflows/ci.yml

@@ -303,8 +303,10 @@ jobs:
       RUSTFLAGS: ''
     steps:
       - uses: actions/checkout@v5
+      - uses: Swatinem/rust-cache@779680da715d629ac1d338a641029a2f4372abb5 # v2.8.2
+        with:
+          shared-key: semver
       - uses: obi1kenobi/cargo-semver-checks-action@v2
-      - run: cargo semver-checks
 
   rustfmt:
     runs-on: ubuntu-latest