Exclude master from build workflow trigger

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

.gitea/workflows/build.yml

@@ -3,6 +3,7 @@ on:
   push:
     branches:
       - '*'
+      - '!master'
 jobs:
   build:
     runs-on: ubuntu-latest