Fix workflow sync lockfiles (2) (eclipse-zenoh#648)

.github/workflows/sync-lockfiles.yml

@@ -10,8 +10,24 @@ defaults:
     shell: bash
 
 jobs:
+  fetch:
+    name: Fetch Zenoh's lockfile
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout Zenoh
+        uses: actions/checkout@v4
+        with:
+          repository: eclipse-zenoh/zenoh
+
+      - name: Upload lockfile
+        uses: actions/upload-artifact@v3
+        with:
+          name: Cargo.lock
+          path: Cargo.lock
+
   sync:
     name: Sync Cargo lockfile with ${{ matrix.dependant }}
+    needs: fetch
     runs-on: ubuntu-latest
     strategy:
       matrix:
@@ -33,6 +49,8 @@ jobs:
       - name: Checkout ${{ matrix.dependant }}
         uses: actions/checkout@v4
         with:
+          repository: eclipse-zenoh/${{ matrix.dependant }}
+          submodules: true
           token: ${{ secrets.BOT_TOKEN_WORKFLOW }}
 
       - name: Install Rust toolchain
@@ -43,25 +61,25 @@ jobs:
       # NOTE: Not all Zenoh dependants have their Cargo manifest and lockfile
       # at the repository's toplevel. The only exception being zenoh-kotlin and
       # zenoh-java. Thus the need for this ugly workaround.
-      - name: Compute Cargo manifest path of ${{ matrix.dependant }}
-        id: manifest-path
+      - name: Compute crate path of ${{ matrix.dependant }}
+        id: crate-path
         run: |
           if [[ "${{ matrix.dependant }}" =~ zenoh-(java|kotlin) ]]; then
-            echo "value=./zenoh-jni/Cargo.toml" >> $GITHUB_OUTPUT
+            echo "value=zenoh-jni" >> $GITHUB_OUTPUT
           else
-            echo "value=./Cargo.toml" >> $GITHUB_OUTPUT
+            echo "value=." >> $GITHUB_OUTPUT
           fi
 
       - name: Override ${{ matrix.dependant }} lockfile with Zenoh's
-        # NOTE: We assume that the lockfile resides in the same directory as the manifest.
-        run: |
-          MANIFEST_PATH=${{ steps.manifest-path.outputs.value }}
-          curl "https://raw.githubusercontent.com/eclipse-zenoh/zenoh/main/Cargo.lock" --output ${MANIFEST_PATH/toml/lock}
+        uses: actions/download-artifact@v3
+        with:
+          name: Cargo.lock
+          path: ${{ steps.crate-path.outputs.value }}
 
       - name: Rectify lockfile
         # NOTE: Checking the package for errors will rectify the Cargo.lock while preserving
         # the dependency versions fetched from source.
-        run: cargo check --manifest-path ${{ steps.manifest-path.outputs.value }}
+        run: cargo check --manifest-path ${{ steps.crate-path.outputs.value }}/Cargo.toml
 
       - name: Create/Update a pull request if the lockfile changed
         id: cpr