fix: Streamline SSH known hosts setup in pull request workflow

- Added a pre-setup step for SSH known hosts using a post-check mechanism.
- Updated `check.sh` execution to occur in a dedicated shell step.
- Optimized logic for Docker installation on macOS.

Author: warnyul

.github/workflows/pull_request.yml

@@ -14,19 +14,24 @@ jobs:
     runs-on: ${{ matrix.os }}      
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - name: Setup post check known hosts
+        uses: pyTooling/Actions/with-post-step@9ceefdbf5dceae8c441fc393ed82344c7ca8bbdb # v3.1.1
+        with:
+          main: |
+            # Do nothing
+            exit 0
+          post: |
+            ./post_check.sh
       - name: Setup SSH key
         uses: ./
         with:
           ssh-private-key: ${{ secrets.SSH_PRIVATE_KEY }}
           ssh-known-hosts: ${{ secrets.SSH_KNOWN_HOSTS }}
           log-public-key: false
-      - name: Check known hosts
-        uses: pyTooling/Actions/with-post-step@9ceefdbf5dceae8c441fc393ed82344c7ca8bbdb # v3.1.1
-        with:
-          main: |
-            ./check.sh
-          post: |
-            ./post_check.sh
+      - name: Setup post check known hosts
+        shell: bash
+        run: |
+          ./check.sh
       - name: Install docker (Missing on MacOS)
         if: runner.os == 'macos'
         shell: bash