ci: run CI on push to master for Codecov baseline (#3365)

Without this, Codecov has no baseline to compare PRs against,
causing codecov/project to always fail.

Author: PierreBrisorgueil

.github/workflows/CI.yml

@@ -1,6 +1,12 @@
 name: CI
 
 on:
+  push:
+    branches: [master, main]
+    paths-ignore:
+      - '**/*.md'
+      - 'documentation/**'
+      - '.claude/**'
   pull_request:
     branches: [master, main]
     paths-ignore: