ci: enable builds on any push to facilitate debugging

According to [official docs][1], the previous definition meant that only
tags that also contain touches to shell scripts are to be built, which
is not what we want. For now we have to first debug the `dotnet
build-server shutdown --vbcscompiler` hanging problem so we have to
remove the workflow restriction anyway...

[1]: https://docs.github.com/en/actions/writing-workflows/choosing-when-your-workflow-runs/events-that-trigger-workflows#running-your-workflow-only-when-a-push-affects-specific-files

Signed-off-by: WANG Xuerui <[email protected]>

.github/workflows/build.yml

@@ -2,13 +2,7 @@ name: Build
 
 on:
   push:
-    paths:
-      - '**.sh'
-    tags:
-      - '*'
   pull_request:
-    paths:
-      - '**.sh'
   merge_group:
     types: [checks_requested]
   # allow manual triggering