refactor: Update devcontainer image name construction in build-devcon…

…tainer.yml

.github/workflows/build-devcontainer.yml

@@ -3,10 +3,14 @@ name: 'build devcontainer image'
 on:
   # rebuild any PRs and main branch changes
   pull_request:
+    files:
+    - '.github/*'
   push:
     branches:
       - main
       - develop
+    files:
+      - '.github/*'
 
 permissions:
   # write-all is too much, but we need to write to packages