Remove concurrency guard from push-only workflow

Author: trask

.github/workflows/build.yml

@@ -10,10 +10,6 @@ on:
 permissions:
   contents: read
 
-concurrency:
-  group: ${{ github.workflow }}-${{ github.sha }}
-  cancel-in-progress: true
-
 jobs:
   common:
     uses: ./.github/workflows/build-common.yml