ci: remove paths-ignore from pull_request trigger

PR #233 only touches .md files, which were excluded by paths-ignore,
causing CI to be skipped entirely. Remove paths-ignore from the
pull_request trigger so all PRs get validated. Keep paths-ignore on
push to avoid unnecessary deploys for docs-only changes to master.

.github/workflows/deploy.yml

@@ -10,11 +10,6 @@ on:
       - 'docs/**'
   pull_request:
     branches: [master]
-    paths-ignore:
-      - '**.md'
-      - 'LICENSE'
-      - '.gitignore'
-      - 'docs/**'
 
 concurrency:
   group: deploy