espressif: Add CI jobs for Secure boot enabled images

Signed-off-by: Gustavo Henrique Nihei <gustavo.nihei@espressif.com>
diff --git a/ci/espressif_install.sh b/ci/espressif_install.sh
index 2528968..db32200 100755
--- a/ci/espressif_install.sh
+++ b/ci/espressif_install.sh
@@ -9,8 +9,13 @@
 
 set -eo pipefail
 
+install_imgtool() {
+    pip install imgtool
+}
+
 install_idf() {
     "${IDF_PATH}"/install.sh
 }
 
+install_imgtool
 install_idf