Adds threshold to code coverage changes for project (#4040)

* Fixes code coverage workflow failures for the project test due to inderect flakey changes

Signed-off-by: Ashwin P Chandran <ashwinpc@amazon.com>

* Adds changelog

Signed-off-by: Ashwin P Chandran <ashwinpc@amazon.com>

---------

Signed-off-by: Ashwin P Chandran <ashwinpc@amazon.com>

Author: ashwin-pc

.github/.codecov.yml

@@ -1,7 +1,11 @@
 # https://docs.codecov.com/docs/codecov-yaml
+codecov:
+  require_ci_to_pass: yes
+
 coverage:
   status:
     project:
       default:
-        # https://docs.codecov.com/docs/commit-status#target
-        target: auto  # coverage must be equal or above the previous commit
+        target: auto
+        threshold: 2% # the leniency in hitting the target
+

CHANGELOG.md

@@ -150,6 +150,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - [CI] Reduce redundancy by using matrix strategy on Windows and Linux workflows ([#3514](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/3514))
 - Add an achievement badger to the PR ([#3721](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/3721))
 - Install chrome driver for functional tests from path set by environment variable `TEST_BROWSER_BINARY_PATH`([#3997](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/3997))
+- Adds threshold to code coverage config to prevent workflow failures ([#4040](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/4040))
 
 ### 📝 Documentation