Add PUSH_COVERITY to mbed-tls-nightly-tests and mbedtls-release-ci-testing

Signed-off-by: Arthur She <arthur.she@linaro.org>
Change-Id: I09b913494d9c3cb4dee1e425ebb7648d05fc6e2e
diff --git a/mbedtls-release-ci-testing.yaml b/mbedtls-release-ci-testing.yaml
index edbc91b..b977295 100644
--- a/mbedtls-release-ci-testing.yaml
+++ b/mbedtls-release-ci-testing.yaml
@@ -106,6 +106,10 @@
 
           For the list of Mbed OS Gold and Silver boards, see <a href="https://confluence.arm.com/display/IoTBU/ISG+Device+SW+SUT+list">here</a>
         name: PLATFORMS_TO_TEST
+    - bool:
+        default: true
+        description: Push head to coverity branch, triggering a scan (development only)
+        name: PUSH_COVERITY
     - git-parameter:
         name: TEST_BRANCH
         description: Branch or tag in https://github.com/arthur-she/mbedtls-test (forks are not supported)