Add concurrency control to build-docs workflow

This commit introduces concurrency control to the GitHub Actions build-docs workflow. Now, only one workflow will run at a time for a given branch, with new runs automatically cancelling in-progress runs. This can prevent unnecessary computing resources usage and ensure the workflow reflects the latest repository state.

.github/workflows/build-docs.yml

@@ -20,6 +20,10 @@ env:
   CONFIG_JSON_PRODUCT: 'HI'
   CONFIG_JSON_VERSION: '1.0'
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   build:
     runs-on: ubuntu-latest