Update mypy and run it on all the files

Running `mypy` only on the changed files is the wrong thing to do, as typing changes in one file can have an effect on upstream code that imports said file.

Apart from removing that file filtering, this also updates the `setup-python` GHA, and `mypy` itself.

.github/workflows/mypy.yml

@@ -6,25 +6,16 @@ on:
       extra_config:
         type: string
         required: false
-        default: ''
-        description: 'Extra configuration for mypy'
+        default: ""
+        description: "Extra configuration for mypy"
 
 jobs:
   static-type-check:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
-    - uses: actions/setup-python@v3
-      with:
-        python-version: '3.12'
-    - run: pip install mypy==1.10.0
-    - name: Get Python changed files
-      id: changed-py-files
-      uses: tj-actions/[email protected]
-      with:
-        files: |
-          *.py
-          **/*.py
-    - name: Run if any of the listed files above is changed
-      if: steps.changed-py-files.outputs.any_changed == 'true'
-      run: mypy ${{ steps.changed-py-files.outputs.all_changed_files }} --ignore-missing-imports ${{ inputs.extra_config }}
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+      - run: pip install mypy==1.13.0
+      - run: mypy . --ignore-missing-imports ${{ inputs.extra_config }}