Swap out deprecated runner (#2349)

Summary:
Github is deprecating the N-core-ubuntu runner label, replacing it with N-core. We need to migrate PyTorch runners accordingly. Turns out github had originally asked for the change to be in the wrong direction

This only affects how github queues jobs, not where those jobs actually run

More details in pytorch/pytorch#125721

Pull Request resolved: #2349

Reviewed By: esantorella

Differential Revision: D57731140

Pulled By: Balandat

fbshipit-source-id: 31c7742bc545bfa6c8e6afd24d7f5edd52229f56

Author: ZainRizvi

.github/workflows/deploy_on_release.yml

@@ -46,7 +46,7 @@ jobs:
 
   package-deploy-conda:
     name: Package conda and deploy to anaconda.org
-    runs-on: 8-core
+    runs-on: 8-core-ubuntu
     needs: tests-and-coverage-pip
     steps:
     - uses: actions/checkout@v4

.github/workflows/nightly.yml

@@ -62,7 +62,7 @@ jobs:
 
   package-conda:
     name: Test conda build
-    runs-on: 8-core
+    runs-on: 8-core-ubuntu
     steps:
     - uses: actions/checkout@v4
     - uses: conda-incubator/setup-miniconda@v3