Schedule GitHub workflows

.github/workflows/bc.yml

@@ -1,6 +1,8 @@
 on:
-    - pull_request
-    - push
+  pull_request:
+  push:
+  schedule:
+    - cron: '0 0 * * *'
 
 name: backwards compatibility
 jobs:

.github/workflows/build.yml

@@ -1,6 +1,8 @@
 on:
-  - pull_request
-  - push
+  pull_request:
+  push:
+  schedule:
+    - cron: '0 0 * * *'
 
 name: build
 

.github/workflows/mutation.yml

@@ -1,8 +1,8 @@
 on:
   pull_request:
   push:
-    branches:
-      - "master"
+  schedule:
+    - cron: '0 0 * * *'
 
 name: mutation test
 

.github/workflows/static.yml

@@ -1,6 +1,8 @@
 on:
-  - pull_request
-  - push
+  pull_request:
+  push:
+  schedule:
+    - cron: '0 0 * * *'
 
 name: static analysis