Update pre-commit GitHub action

Author: mxr

.github/workflows/pre-commit.yml

@@ -9,12 +9,6 @@ jobs:
   pre-commit:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v1
-    - uses: actions/setup-python@v1
-    - name: set PY
-      run: echo "::set-env name=PY::$(python -c 'import hashlib, sys;print(hashlib.sha256(sys.version.encode()+sys.executable.encode()).hexdigest())')"
-    - uses: actions/cache@v1
-      with:
-        path: ~/.cache/pre-commit
-        key: pre-commit|${{ env.PY }}|${{ hashFiles('.pre-commit-config.yaml') }}
-    - uses: pre-commit/[email protected]
+    - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+    - uses: pre-commit/[email protected]

.pre-commit-config.yaml

@@ -52,6 +52,6 @@ repos:
     -   id: pyupgrade
         args: [--py36-plus]
 -   repo: https://github.com/pre-commit/mirrors-mypy
-    rev: v0.770
+    rev: v0.800
     hooks:
     -   id: mypy