fix: use $GITHUB_ACTION_PATH to avoid bash backslash escaping on Windows runners (#298)

The ${{ github.action_path }} template expression resolves to a backslash
path on Windows (D:\a\_actions\...\v0.1.14). When inlined into a bash run
block, bash treats backslashes as escape sequences, mangling the path.

Switching to the auto-injected $GITHUB_ACTION_PATH env var routes through
shell variable expansion, which preserves the literal value.

Fixes #150.

Co-authored-by: aditya <aditya@rapidcircuitry.com>

action.yml

@@ -42,14 +42,14 @@ runs:
     - name: Build conformance tests
       shell: bash
       run: |
-        cd "${{ github.action_path }}"
+        cd "$GITHUB_ACTION_PATH"
         npm ci
         npm run build
 
     - name: Run conformance tests
       shell: bash
       run: |
-        CONFORMANCE="${{ github.action_path }}/dist/index.js"
+        CONFORMANCE="$GITHUB_ACTION_PATH/dist/index.js"
 
         # Build the command arguments
         ARGS="${{ inputs.mode }}"