Add instructions for testing local changes with samples (#196)

Author: MarkusBillharz

CONTRIBUTING.md

@@ -81,6 +81,12 @@ See [How to Write a Git Commit Message](https://chris.beams.io/posts/git-commit/
 * Run `./gradlew test` to test the module and speed up development.
 * Run `./gradlew build` to build the project, which also runs all the tests.
 
+### Running Samples with Local Changes
+
+All sample projects include mavenLocal() in their repositories and will prioritize locally published builds by default.
+
+* Run `./gradlew publishToMavenLocal` to test the samples with local changes to the SDK
+
 ## Contacting maintainers
 
 * If something cannot be done, not convenient, or does not work — submit an [issue](#submitting-issues).