Restrict github actions for pushes to main/master (#1383)

.github/workflows/disperse.yml

@@ -2,7 +2,8 @@
 name: Disperse configuration
 
 "on":
-  - push
+  push:
+    branches: [ main, master ]
 
 jobs:
   build:

.github/workflows/docs.yml

@@ -3,6 +3,7 @@ name: API Docs
 
 on:
   push:
+    branches: [ main, master ]
   pull_request:
   schedule:
     - cron: "0 6 * * *" # Daily 6AM UTC build

.github/workflows/python-distributions.yml

@@ -2,6 +2,7 @@ name: Build Python distributions
 
 on:
   push:
+    branches: [ main, master ]
   pull_request:
   schedule:
     - cron: "0 6 * * *" # Daily 6AM UTC build

.github/workflows/pythontest.yml

@@ -2,6 +2,7 @@ name: Python tests
 
 on:
   push:
+    branches: [ main, master ]
   pull_request:
   schedule:
     - cron: "0 6 * * *" # Daily 6AM UTC build