fix syntax

.github/workflows/integration_tests.yml

@@ -1,6 +1,6 @@
 name: Run Integration Tests
-on: {}
-
+on:
+  workflow_dispatch:
 jobs:
   run_integration_tests:
     runs-on: ubuntu-latest

.github/workflows/jbpresubmit.yml

@@ -5,8 +5,8 @@
 
 # The aim of this workflow is to run checks and some tests before submitting the CL upstream.
 name: JB-COMPOSE-variant of AndroidX Presubmits
-on: {}
-
+on:
+  workflow_dispatch:
 jobs:
   setup:
     runs-on: ubuntu-latest

.github/workflows/presubmit.yml

@@ -1,6 +1,6 @@
 name: AndroidX Presubmits
-on: {}
-
+on:
+  workflow_dispatch:
 env:
   # Allow precise monitoring of the save/restore of Gradle User Home by `gradle-build-action`
   # See https://github.com/marketplace/actions/gradle-build-action?version=v2.1.1#cache-debugging-and-analysis

.github/workflows/prune_artifacts.yml

@@ -1,6 +1,6 @@
 name: "Prune old artifacts"
-on: {}
-
+on:
+  workflow_dispatch:
 jobs:
   delete-artifacts:
     runs-on: ubuntu-latest

.github/workflows/register_workflow_start.yml

@@ -1,6 +1,6 @@
 name: Register Workflow Run with AndroidX
-on: {}
-
+on:
+  workflow_dispatch:
 jobs:
   ping_androidx_dev:
     if: ${{ !github.event.repository.fork }}

.github/workflows/scorecards.yml

@@ -1,6 +1,6 @@
 name: Scorecards supply-chain security
-on: {}
-
+on:
+  workflow_dispatch:
 # Declare default permissions as read only.
 permissions: read-all
 

.github/workflows/update_prebuilts.yml

@@ -2,8 +2,8 @@
 # To run it, navigate to https://github.com/androidx/androidx/actions/workflows/update_prebuilts.yml
 # and click "Run workflow"
 name: Update Prebuilts
-on: {}
-jobs:
+on:
+  workflow_dispatch:jobs:
   update-prebuilts:
     runs-on: ubuntu-latest
     steps: