GH Actions: pin re-usable workflows too

Follow up on 380, which added commit hash pinning to all externally managed action runners, this commit now also adds this to the re-usable workflows managed in the `PHPCSStandards/.github` repository.

Author: jrfnl

.github/workflows/basics.yml

@@ -138,20 +138,20 @@ jobs:
 
   phpstan:
     name: "PHPStan"
-    uses: PHPCSStandards/.github/.github/workflows/reusable-phpstan.yml@main
+    uses: PHPCSStandards/.github/.github/workflows/reusable-phpstan.yml@9d51cbe2ff0bde5f7f5b2cf7608e9e13d593c6f2 # v1.0.0
     with:
       phpstanVersion: '2.x'
 
   markdownlint:
     name: 'Lint Markdown'
-    uses: PHPCSStandards/.github/.github/workflows/reusable-markdownlint.yml@main
+    uses: PHPCSStandards/.github/.github/workflows/reusable-markdownlint.yml@9d51cbe2ff0bde5f7f5b2cf7608e9e13d593c6f2 # v1.0.0
 
   remark:
     name: 'QA Markdown'
-    uses: PHPCSStandards/.github/.github/workflows/reusable-remark.yml@main
+    uses: PHPCSStandards/.github/.github/workflows/reusable-remark.yml@9d51cbe2ff0bde5f7f5b2cf7608e9e13d593c6f2 # v1.0.0
 
   yamllint:
     name: 'Lint Yaml'
-    uses: PHPCSStandards/.github/.github/workflows/reusable-yamllint.yml@main
+    uses: PHPCSStandards/.github/.github/workflows/reusable-yamllint.yml@9d51cbe2ff0bde5f7f5b2cf7608e9e13d593c6f2 # v1.0.0
     with:
       strict: true