Add an issue template for Code Improvement (#8960)

Author: daniellepintz

.github/ISSUE_TEMPLATE/code_improvement.md

@@ -0,0 +1,39 @@
+---
+name: Code improvement
+about: Suggest a code improvement, i.e. refactoring, deprecation, etc.
+title: ''
+labels: enhancement, help wanted, refactors / code health
+assignees: ''
+---
+
+## Proposed refactoring or deprecation
+
+<!-- A clear and concise description of the code improvement -->
+
+### Motivation
+
+<!-- Please outline the motivation for the proposal. If this is related to another GitHub issue, please link here too -->
+
+### Pitch
+
+<!-- A clear and concise description of what you want to happen. -->
+
+### Additional context
+
+<!-- Add any other context or screenshots here. -->
+
+______________________________________________________________________
+
+#### If you enjoy Lightning, check out our other projects! ⚡
+
+<sub>
+
+- [**Metrics**](https://github.com/PyTorchLightning/metrics): Machine learning metrics for distributed, scalable PyTorch applications.
+
+- [**Flash**](https://github.com/PyTorchLightning/lightning-flash): The fastest way to get a Lightning baseline! A collection of tasks for fast prototyping, baselining, finetuning and solving problems with deep learning
+
+- [**Bolts**](https://github.com/PyTorchLightning/lightning-bolts): Pretrained SOTA Deep Learning models, callbacks and more for research and production with PyTorch Lightning and PyTorch
+
+- [**Lightning Transformers**](https://github.com/PyTorchLightning/lightning-transformers): Flexible interface for high performance research using SOTA Transformers leveraging Pytorch Lightning, Transformers, and Hydra.
+
+</sub>