set RUSTFLAGS for cargo dist in libsql-server-release GA

Author: sivukhin

.github/workflows/libsql-server-release.yml

@@ -54,6 +54,7 @@ jobs:
       publishing: ${{ !github.event.pull_request }}
     env:
       GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      RUSTFLAGS: --cfg tokio_unstable
     steps:
       - uses: actions/checkout@v4
         with:
@@ -104,6 +105,7 @@ jobs:
     env:
       GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       BUILD_MANIFEST_NAME: target/distrib/${{ join(matrix.targets, '-') }}-dist-manifest.json
+      RUSTFLAGS: --cfg tokio_unstable
     steps:
       - name: enable windows longpaths
         run: |
@@ -161,6 +163,7 @@ jobs:
     env:
       GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       BUILD_MANIFEST_NAME: target/distrib/global-dist-manifest.json
+      RUSTFLAGS: --cfg tokio_unstable
     steps:
       - uses: actions/checkout@v4
         with:
@@ -204,6 +207,7 @@ jobs:
     if: ${{ always() && needs.plan.outputs.publishing == 'true' && (needs.build-global-artifacts.result == 'skipped' || needs.build-global-artifacts.result == 'success') && (needs.build-local-artifacts.result == 'skipped' || needs.build-local-artifacts.result == 'success') }}
     env:
       GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      RUSTFLAGS: --cfg tokio_unstable
     runs-on: "ubuntu-20.04"
     outputs:
       val: ${{ steps.host.outputs.manifest }}