security: add least-privilege permissions to import workflows

.github/workflows/import_cambridge_events.yml

@@ -7,6 +7,8 @@ on:
   push:
     branches:
       - 'apify_integration_cambridge'
+permissions: {}
+
 jobs:
   build:
     name: Import City of Cambridge events

.github/workflows/import_eventbrite_events.yml

@@ -7,6 +7,8 @@ on:
   push:
     branches:
       - 'eventbrite_integration'
+permissions: {}
+
 jobs:
   build:
     name: Import Eventbrite events

.github/workflows/import_explore_waterloo_events.yml

@@ -7,6 +7,8 @@ on:
   push:
     branches:
       - 'explore_integration'
+permissions: {}
+
 jobs:
   build:
     name: Import Explore Waterloo events

.github/workflows/import_kitchener_events.yml

@@ -7,6 +7,8 @@ on:
   push:
     branches:
       - 'apify_integration_kitchener'
+permissions: {}
+
 jobs:
   build:
     name: Import City of Kitchener events

.github/workflows/import_museums_events.yml

@@ -7,6 +7,8 @@ on:
   push:
     branches:
       - 'apify_integration_museums'
+permissions: {}
+
 jobs:
   build:
     name: Import RoW museums events

.github/workflows/import_waterloo_events.yml

@@ -7,6 +7,8 @@ on:
   push:
     branches:
       - 'waterloo_integration'
+permissions: {}
+
 jobs:
   build:
     name: Import City of Waterloo events

.github/workflows/import_wpl_events.yml

@@ -7,6 +7,8 @@ on:
   push:
     branches:
       - 'wpl_integration'
+permissions: {}
+
 jobs:
   build:
     name: Import WPL events