Disable nightly-main test job

Author: plemarquand

.github/workflows/pull_request.yml

@@ -22,6 +22,7 @@ jobs:
     name: Test
     uses: swiftlang/github-workflows/.github/workflows/swift_package_test.yml@main
     with:
+      linux_exclude_swift_versions: "[{\"swift_version\": [\"nightly-main\"]}]"
       linux_env_vars: |
         NODE_VERSION=v18.19.0
         NODE_PATH=/usr/local/nvm/versions/node/v18.19.0/bin