tf-a-main.yaml: Add JOBS_REFSPEC

Added a JOBS_REFSPEC parameter to the tf-a-main job,
allowing users to specify which branch to use.

Change-Id: Ie5d2cebdc4465e6831dbbba80673bcc91624b289
Signed-off-by: Arthur She <arthur.she@linaro.org>
diff --git a/tf-a-main.yaml b/tf-a-main.yaml
index febe729..16f7417 100644
--- a/tf-a-main.yaml
+++ b/tf-a-main.yaml
@@ -43,6 +43,11 @@
             name: CI_REFSPEC
             default: '+refs/heads/master:refs/remotes/origin/master'
         - string:
+            name: JOBS_REFSPEC
+            default: 'refs/heads/master'
+            description: |
+              tf-a-job-configs refspec to use. The master branch is used by default.
+        - string:
             name: MBEDTLS_URL
             default: 'https://github.com/Mbed-TLS/mbedtls/archive/mbedtls-3.6.2.tar.gz'
         - string: