Quote arguments to check.sh

Without this quoting, arguments would get expanded before being passed
to bash, which would cause the following configuration to fail:

    clang-format-version: 12
    check-path: '.'
    exclude-regex: '(foo|bar)'

because `check.sh` would get run as:

    check.sh 12 . LLVM (foo|bar)

And since '(' and '|' are special characters for bash, the action will
immediately fail because of a syntax error.

Instead, it should get ran as:

    check.sh "12" "." "LLVM" "(foo|bar)"

action.yml

@@ -26,5 +26,6 @@ inputs:
 runs:
   using: "composite"
   steps:
-    - run: ${{ github.action_path }}/check.sh  ${{ inputs.clang-format-version }} ${{ inputs.check-path }} ${{ inputs.fallback-style }} ${{ inputs.exclude-regex }}
+    - run: >
+        "${{ github.action_path }}/check.sh" "${{ inputs.clang-format-version }}" "${{ inputs.check-path }}" "${{ inputs.fallback-style }}" "${{ inputs.exclude-regex }}"
       shell: bash