stop testing old things

.circleci/config.yml

@@ -9,18 +9,6 @@ shared_configs:
 # Use the latest 2.1 version of CircleCI pipeline process engine. See: https://circleci.com/docs/2.0/configuration-reference
 version: 2.1
 jobs:
-  build-1-15:
-    working_directory: ~/repo
-    docker:
-      - image: cimg/go:1.15
-    steps: *simple_job_steps
-
-  build-1-16:
-    working_directory: ~/repo
-    docker:
-      - image: cimg/go:1.16
-    steps: *simple_job_steps
-
   build-1-17:
     working_directory: ~/repo
     docker:
@@ -42,8 +30,6 @@ jobs:
 workflows:
   pr-build-test:
     jobs:
-      - build-1-15
-      - build-1-16
       - build-1-17
       - build-1-18
       - build-1-19