ci: coverage workflow is to be run manually

it's not really used, but slows down other workflows, so it made sense to disable automatic triggering

.github/workflows/coverage.yml

@@ -2,9 +2,10 @@ name: 📊 Code coverage test
 run-name: 📊 Code coverage test ${{ github.sha }}
 
 on:
- workflow_run:
-   workflows: [ 🔬 Test ]
-   types: [ completed ]
+# workflow_run:
+#   workflows: [ 🔬 Test ]
+#   types: [ completed ]
+  workflow_dispatch:
 
 # cancels the previous workflow run when a new one appears in the same branch (e.g. master or a PR's branch)
 concurrency: