ci: run github work flow only for pull request

currently github action are getting trigerred for
both pull and push request, this commits removes the
action for push  events.

Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>

.github/workflows/codespell.yaml

@@ -4,14 +4,9 @@
 name: Codespell
 # yamllint disable-line rule:truthy
 on:
-  push:
-    tags:
-      - v*
-    branches:
-      - master
   pull_request:
     branches:
-      - master
+      - '*'
 jobs:
   codespell:
     name: codespell