Fix variable name

Author: kisantia

.github/workflows/trigger-update-galleries-pipeline.yml

@@ -19,4 +19,4 @@ jobs:
         azure-devops-project-url: 'https://dev.azure.com/msdata/SQLToolsAndLibraries'
         azure-pipeline-name: 'Update AzureDataStudio Extensions Gallery' # name of the Azure pipeline to be triggered
         azure-devops-token: '${{ secrets.ADO_UPDATE_GALLERIES_TOKEN }}'
-        azure-pipeline-variables: '{"triggeringBranch": $GITHUB_REF_NAME}' # pass branch name to pipeline
+        azure-pipeline-variables: '{"githubBranch": "$GITHUB_REF_NAME"}' # pass branch name to pipeline