test: run mypy in test-src not in GH actions

.github/workflows/checks.yml

@@ -74,15 +74,3 @@ jobs:
             -k autopep8 \
             --rootdir=. \
             -v
-
-  mypy:
-    name: "Mypy check"
-    runs-on: ubuntu-latest
-    steps:
-      - name: Clone repo
-        uses: actions/checkout@v2
-      - name: Check files with mypy
-        run: |
-          sudo apt install python3-pip -y
-          sudo pip install mypy types-pyyaml jsonschema mako
-          mypy osbuild