ci: fix new error

.github/workflows/main.yml

@@ -18,6 +18,8 @@ jobs:
     - uses: actions/checkout@v2
     - uses: actions/setup-python@v1
     - name: set PY
+      env:
+        ACTIONS_ALLOW_UNSECURE_COMMANDS: true
       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: