docs: add validation guide for testing changes in real applications (#37)

Author: cassiofariasmachado

docs/DEVELOPMENT.md

@@ -1,11 +1,13 @@
 # Development Guide
 
 ## Requirements
+
 - Python 3.11+
 - uv (package manager)
 - Docker
 
 ## Setup
+
 ```bash
 # Clone the repository
 git clone https://github.com/SAP/cloud-sdk-python.git
@@ -42,6 +44,7 @@ uv build
 ```
 
 ## Code Guidelines
+
 - [Code Guidelines](GUIDELINES.md)
 
 ## Tests
@@ -60,14 +63,43 @@ uv run pytest -m integration -v
 See [Integration Tests](INTEGRATION_TESTS.md) for more details on integration testing.
 
 ### Coverage
+
 ```bash
 # Basic coverage
 uv run pytest --cov=src
 ```
 
+## Validating changes in a real application
+
+Sometimes we want to validate our changes in a real application before publishing them to PyPI. It's extremely important to test like that to ensure that there are no issues with our changes and we encourage contributors to do so.
+
+For that, we can reference the package using the GitHub endpoint in the `requirements.txt` or `pyproject.toml` of the test application. This way, we can install the package directly from the branch, commit, or tag that contains our changes without needing to publish it to PyPI first.
+
+Using `requirements.txt`:
+
+```bash
+# Other dependencies...
+sap-cloud-sdk @ git+https://github.com/sap/cloud-sdk-python@<branch-or-commit-or-tag>
+# You also could use your forked repository if you have one, for example:
+sap-cloud-sdk @ git+https://github.com/your-username/cloud-sdk-python@<branch-or-commit-or-tag>
+```
+
+Using `pyproject.toml`:
+
+```toml
+dependencies = [
+    # Other dependencies...
+    "sap-cloud-sdk @ git+https://github.com/sap/cloud-sdk-python@<branch-or-commit-or-tag>"
+    # You also could use your forked repository if you have one, for example:
+    "sap-cloud-sdk @ git+https://github.com/your-username/cloud-sdk-python@<branch-or-commit-or-tag>"
+]
+```
+
+See the pip official documentation for more details on installing packages from VCS like Git: [VCS Support](https://pip.pypa.io/en/stable/topics/vcs-support/#vcs-support)
+
 ## Release and Deployment
 
-For the end-to-end process to cut a release and publish artifacts, see the [Release and Deployment Guide](RELEASE.md).:
+For the end-to-end process to cut a release and publish artifacts, see the [Release and Deployment Guide](RELEASE.md).
 
 ## Contributing
 For guidance on contributing with new features, see the [Contributing Guide](../CONTRIBUTING.md).