Update the environment variable to PSGALLERY_API_KEY

Author: HeyItsGilbert

.github/workflows/publish.yaml

@@ -29,7 +29,7 @@ jobs:
       - name: Build and publish
         if: steps.check_if_versions_bumped.outputs.version_bumped == 'True'
         env:
-          NUGET_KEY: ${{ secrets.NUGET_KEY }}
+          PSGALLERY_API_KEY: ${{ secrets.NUGET_KEY }}
         shell: pwsh
         run: |
           ./build.ps1 -Task Publish