ci: rename workflow to CI for badge consistency across ecosystem

Aligns the CI badge label with the RVC ecosystem's other repos, which
already show a consistent "CI" badge rather than a repo-specific
workflow name.

Author: petercorke

.github/workflows/master.yml

@@ -2,7 +2,7 @@
 # This workflow will install Python dependencies, run tests and lint with a variety of Python versions
 # For more information see: https://help.github.com/actions/language-and-framework-guides/using-python-with-github-actions
 
-name: build
+name: CI
 
 on:
   push: