Add pull request template and udpate contributor guide

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,18 @@
+# Description
+
+<!-- Please include a summary of the change and which issue is fixed. -->
+
+Fixes # (issue)
+
+### Checklist:
+
+- [ ] I have ran `./ci/run_stable_checks.sh`
+- [ ] I have performed a self-review of my own code
+- [ ] I have added tests that prove my fix is effective or that my feature works -->
+
+<!-- Performance Improvements Only -->
+<!-- 1. Fork and clone https://github.com/yewstack/js-framework-benchmark -->
+<!-- 2. Update `frameworks/yew/Cargo.toml` with your fork of Yew and the branch for this PR -->
+<!-- 3. Open a new PR with your `Cargo.toml` changes -->
+<!-- 4. Paste a link to the benchmark results: -->
+<!-- - [ ] I have opened a PR against https://github.com/yewstack/js-framework-benchmark -->

CONTRIBUTING.md

@@ -56,3 +56,13 @@ or
 ```bash
 cargo test --target wasm32-unknown-unknown --features wasm_test
 ```
+
+#### Benchmarks
+
+If you wish to improve the performance of Yew, we request that you prove the improvements of your changes with benchmarks.
+
+1. Fork and clone https://github.com/yewstack/js-framework-benchmark
+2. Update `frameworks/yew/Cargo.toml` with your fork of Yew and the branch for your changes
+3. Open a new PR with your `Cargo.toml` changes
+
+Feel free to add new benchmark tests if the current benchmark coverage is insufficient!