Bump CircleCI Go to version 1.18 (#122)

Bump go to version 1.18

Author: zackproser

.circleci/config.yml

@@ -1,6 +1,6 @@
 defaults: &defaults
   docker:
-    - image: 087285199408.dkr.ecr.us-east-1.amazonaws.com/circle-ci-test-image-base:go1.16-go111module
+    - image: 087285199408.dkr.ecr.us-east-1.amazonaws.com/circle-ci-test-image-base:go1.18-tf1.4-tg39.1-pck1.8-ci50.7
   environment: 
     TERRATEST_LOG_PARSER_VERSION: NONE
     TERRAFORM_VERSION: NONE