workflows,release: Ship *all* the rust vendored code

Instead of only vendoring the code needed by the agent, let's ensure we
vendor all the needed rust code, and let's do it using the newly
introduced enerate_vendor.sh script.

Fixes: #3973

Signed-off-by: Fabiano Fidêncio <fabiano.fidencio@intel.com>
(cherry picked from commit 3606923ac8)

.github/workflows/release.yaml

@@ -140,13 +140,10 @@ jobs:
       - uses: actions/checkout@v2
       - name: generate-and-upload-tarball
         run: |
-          pushd $GITHUB_WORKSPACE/src/agent
-          cargo vendor >> .cargo/config
-          popd
           tag=$(echo $GITHUB_REF | cut -d/ -f3-)
           tarball="kata-containers-$tag-vendor.tar.gz"
           pushd $GITHUB_WORKSPACE
-          tar -cvzf "${tarball}" src/agent/.cargo/config src/agent/vendor
+          bash -c "tools/packaging/release/generate_vendor.sh ${tarball}"
           GITHUB_TOKEN=${{ secrets.GIT_UPLOAD_TOKEN }} hub release edit -m "" -a "${tarball}" "${tag}" 
           popd