Don't use hardcoded branch name in doc generation

[hudsonm62]

The URL to devcontainer-template.json uses a hardcoded path to main branch, when in reality not everyone will be using the main branch.

Instead, it should be generated based on the current branch name in context (which could be master, dev, version numbers, and so on) - AND/OR add an input parameter to override it

action/src/generateDocs.ts

Line 121 in c40c27d

urlToConfig = `https://github.com/${srcInfo.owner}/${srcInfo.repo}/blob/main/${basePathTrimmed}/${f}/${metadataFile}`;