Fix job definition syntax in migration tutorial

Author: NenoLoje

content/actions/tutorials/migrate-to-github-actions/manual-migrations/migrate-from-azure-pipelines.md

@@ -216,7 +216,7 @@ jobs:
     dependsOn: initial
     steps:
       - script: echo "This job will run after the initial job, in parallel with fanout1."
-  - job: fanin:
+  - job: fanin
     pool:
       vmImage: 'ubuntu-latest'
     dependsOn: [fanout1, fanout2]