Update contributing tests guide to just test core (#1711)

contributing.md

@@ -34,15 +34,13 @@ _Note: If you are running Bazel on a **Mac**, this or any step that requires bui
 
 ### Test
 
-The following command runs all unit tests:
+The following command runs tests for @dataform/core:
 
 ```bash
-bazel test --build_tests_only -- ... -tests/integration/...
+bazel test //core/...
 ```
 
-This runs all tests excluding those that rely on encrypted secrets. If you need to run integration tests, please [get in touch](mailto:opensource@dataform.co) with the team.
-
-_Note: A `java failed` error suggests that Java needs to be installed._
+If you need to run integration tests, that rely on encrypted secrets, please [get in touch](mailto:opensource@dataform.co) with the team.
 
 ### Building