moves mypy type checking out of main check action (#612)

* moves mypy type checking out of main check action

* adds scheduled execution

.github/workflows/check.yml

@@ -25,23 +25,6 @@ jobs:
 
       - run: ruff format --check
 
-  mypy:
-    name: MyPy
-    runs-on: ubuntu-20.04
-
-    steps:
-      - uses: actions/checkout@v3
-
-      - uses: actions/setup-python@v4
-        with:
-          python-version: "3.11"
-
-      - name: Install mypy
-        run: pip install mypy==0.950
-
-      - name: Run
-        run: python3 internal/typecheck.py
-
   nbconvert:
     name: NbConvert
     runs-on: ubuntu-20.04

.github/workflows/typecheck.yml

@@ -0,0 +1,24 @@
+name: Typecheck
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: "17 16 * * *"
+    # Run on main every day at 16:17 UTC
+
+jobs:
+  mypy:
+    name: MyPy
+    runs-on: ubuntu-20.04
+
+    steps:
+      - uses: actions/checkout@v3
+
+      - uses: actions/setup-python@v4
+        with:
+          python-version: "3.11"
+
+      - name: Install mypy
+        run: pip install mypy==0.950
+
+      - name: Run
+        run: python3 internal/typecheck.py