apply GHA security improvements suggested by zizmor

.github/workflows/check-formatting.yml

@@ -11,6 +11,8 @@ jobs:
     steps:
       - name: Checkout code
         uses: actions/checkout@v3
+        with:
+          persist-credentials: false
 
       - name: Run black to check formatting
         uses: psf/black@stable

.github/workflows/on-call-reminder.yml

@@ -12,6 +12,8 @@ jobs:
     steps:
       - name: Checkout code
         uses: actions/checkout@v3
+        with:
+          persist-credentials: false
 
       - name: Set up Python
         uses: actions/setup-python@v4

.github/workflows/run-coverage.yml

@@ -33,12 +33,14 @@ jobs:
       if: inputs.ref != ''
       with:
         ref: ${{ inputs.ref }}
+        persist-credentials: false
 
     - name: Checkout current branch
       uses: actions/checkout@v3
       if: inputs.ref == ''
       with:
         ref: ${{ github.ref }}
+        persist-credentials: false
 
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v4

.github/workflows/run-simulators.yml

@@ -88,12 +88,13 @@ jobs:
             HOSTNAME: ${{ secrets.SSH_HOST }}
             USER_NAME: ${{ secrets.SSH_USERNAME }}
             GH_ACCESS_TOKEN: ${{ secrets.GH_ACCESS_TOKEN }}
+            GH_REF: ${{ github.ref }}
           run: |
             echo "$PRIVATE_KEY" > private_key && chmod 600 private_key
             ssh -o StrictHostKeyChecking=no -i private_key ${USER_NAME}@${HOSTNAME} '
               cd /home/ubuntu/actions/ &&
               rm -rf Scenic &&
-              git clone --branch $(basename "${{ github.ref }}") --single-branch https://[email protected]/BerkeleyLearnVerify/Scenic.git &&
+              git clone --branch $(basename "${GH_REF}") --single-branch https://[email protected]/BerkeleyLearnVerify/Scenic.git &&
               cd Scenic &&
               python3 -m venv venv &&
               source venv/bin/activate &&

.github/workflows/run-tests.yml

@@ -47,12 +47,14 @@ jobs:
       if: inputs.ref != ''
       with:
         ref: ${{ inputs.ref }}
+        persist-credentials: false
 
     - name: Checkout current branch
       uses: actions/checkout@v3
       if: inputs.ref == ''
       with:
         ref: ${{ github.ref }}
+        persist-credentials: false
 
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v4
@@ -69,5 +71,8 @@ jobs:
         python -m pip install -e ".[test-full]"
 
     - name: Run pytest
+      env:
+        TEST_OPTIONS: ${{ inputs.options || (matrix.slow && '--no-graphics' || '--fast --no-graphics') }}
+      shell: sh
       run: |
-        pytest ${{ inputs.options || (matrix.slow && '--no-graphics' || '--fast --no-graphics') }}
+        pytest ${TEST_OPTIONS}