fix: include Java version in Cargo cache key for rust tests

The linux-test-rust job caches native/target which contains JNI-related
build artifacts. Without Java version in the cache key, Java 11 and 17
jobs could restore incompatible cached artifacts from each other.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: andygrove

.github/workflows/pr_build_linux.yml

@@ -114,9 +114,9 @@ jobs:
             ~/.cargo/registry
             ~/.cargo/git
             native/target
-          key: ${{ runner.os }}-cargo-debug-${{ hashFiles('native/**/Cargo.lock', 'native/**/Cargo.toml') }}
+          key: ${{ runner.os }}-cargo-debug-java${{ matrix.java_version }}-${{ hashFiles('native/**/Cargo.lock', 'native/**/Cargo.toml') }}
           restore-keys: |
-            ${{ runner.os }}-cargo-debug-
+            ${{ runner.os }}-cargo-debug-java${{ matrix.java_version }}-
 
       - name: Rust test steps
         uses: ./.github/actions/rust-test