upgrade to the image: cimg/go:1.21 in build (#1141)

* skip the integration test because of go v1.13.4 in image: shimit/mbt_multi:0.3.0

* upgrade to image: cimg/go:1.21 in build

---------

Co-authored-by: Jiang, Yu-tao <>

Author: yutaoj

.circleci/config.yml

@@ -94,7 +94,7 @@ jobs:
 
   build:
     docker:
-      - image: cimg/go:1.19
+      - image: cimg/go:1.21
     environment:
     working_directory: ~/go/src/github.com/SAP/cloud-mta-build-tool
     steps: