fix: no error if bin directory exists

Problem
When one wants to use hadolint-gh-action multiple times, an error is raised because the bin directory already exists, see jbergstroem#134

Solution
Use option -p of mkdir

action.yml

@@ -47,7 +47,7 @@ runs:
       shell: bash
       run: |
         echo "::debug::Downloading Hadolint ${{ inputs.version }}"
-        mkdir ${{ github.action_path }}/bin
+        mkdir -p ${{ github.action_path }}/bin
         curl -L -s -o ${{ github.action_path }}/bin/hadolint \
           "https://github.com/hadolint/hadolint/releases/download/v${{ inputs.version }}/hadolint-Linux-x86_64"
         chmod +x ${{ github.action_path }}/bin/hadolint