ensure nightly builds don't run for forks

.github/workflows/master.yml

@@ -36,6 +36,8 @@ jobs:
 
   check_core:
     name: Check Core
+    # Don't run nightly builds for forks.
+    if: github.repository == 'allenai/allennlp' || github.event_name != 'schedule'
     runs-on: ubuntu-latest
     strategy:
       matrix:
@@ -104,6 +106,8 @@ jobs:
 
   check_models:
     name: Check Models
+    # Don't run nightly builds for forks.
+    if: github.repository == 'allenai/allennlp' || github.event_name != 'schedule'
     runs-on: ubuntu-latest
     strategy:
       matrix:
@@ -150,6 +154,8 @@ jobs:
   # Builds package distribution files for PyPI.
   build_package:
     name: Build Package
+    # Don't run nightly builds for forks.
+    if: github.repository == 'allenai/allennlp' || github.event_name != 'schedule'
     runs-on: ubuntu-latest
 
     steps:
@@ -216,6 +222,8 @@ jobs:
   # Tests installing from the distribution files.
   test_package:
     name: Test Package
+    # Don't run nightly builds for forks.
+    if: github.repository == 'allenai/allennlp' || github.event_name != 'schedule'
     needs: [build_package]  # needs the package artifact created from 'build_package' job.
     runs-on: ubuntu-latest
     strategy:
@@ -253,6 +261,8 @@ jobs:
   # Builds Docker image from the core distribution files and uploads to Docker Hub.
   docker:
     name: Docker
+    # Don't run nightly builds for forks.
+    if: github.repository == 'allenai/allennlp' || github.event_name != 'schedule'
     needs: [build_package]  # needs the package artifact created from 'build_package' job.
     runs-on: ubuntu-latest
 
@@ -305,6 +315,8 @@ jobs:
   # allennlp-docs repo.
   docs:
     name: Docs
+    # Don't run nightly builds for forks.
+    if: github.repository == 'allenai/allennlp' || github.event_name != 'schedule'
     runs-on: ubuntu-latest
 
     steps: