Avoid duplicate CI checks on pull request branches

.github/workflows/lint.yml

@@ -1,5 +1,9 @@
 name: Lint
-on: [push, pull_request]
+on:
+  push:
+    branches:
+      - main
+  pull_request:
 jobs:
   rubocop:
     name: RuboCop

.github/workflows/test.yml

@@ -1,6 +1,10 @@
 ---
 name: test
-on: [push, pull_request]
+on:
+  push:
+    branches:
+      - main
+  pull_request:
 jobs:
   test:
     runs-on: ubuntu-latest

CHANGELOG.md

@@ -1,5 +1,6 @@
 ### 0.5.0 (Next)
 
+* [#27](https://github.com/dblock/ruby-link-checker/pull/27): Avoided duplicate test and lint runs by checking pull requests and pushes to `main` only - [@dblock](https://github.com/dblock), [@Copilot](https://github.com/Copilot).
 * [#26](https://github.com/dblock/ruby-link-checker/pull/26): Added ruby-gem-release automation with manual, dry-run-first releases and RubyGems Trusted Publishing - [@dblock](https://github.com/dblock), [@Copilot](https://github.com/Copilot).
 * [#23](https://github.com/dblock/ruby-link-checker/pull/23): Fixed chained relative redirects, bounded redirect following with `max_redirects`, enabled plain HTTP in the Net::HTTP checker, and corrected retry documentation - [@dblock](https://github.com/dblock), [@Copilot](https://github.com/Copilot).
 * [#24](https://github.com/dblock/ruby-link-checker/pull/24): Added transient-only retries, opt-in retry delays/backoff/jitter and `Retry-After` handling, transport error categories, and an Async concurrency limit - [@dblock](https://github.com/dblock), [@Copilot](https://github.com/Copilot).