ci: change name of ci environment to 'ci-branch-main' to avoid terraf…

…orm issues (#301)

Terraform has a hard time tearing down and recreating whole environments when they are
too far out of date. Instead, this starts a brand new environment named 'ci-branch-main'.

Changing name as short-term fix, long-term fix we will want to dynamically change the 
env name.  This work will be tracked by #302

.github/workflows/tests-main.yaml

@@ -69,7 +69,7 @@ jobs:
         name: 'Run E2E Tests'
         run: "./tools/e2e_test_job.sh"
         env:
-          ENVIRONMENT_NAME: "ci-main"
+          ENVIRONMENT_NAME: "ci-branch-main"
           NODEPOOL_SERVICEACCOUNT_EMAIL: "${{secrets.NODEPOOL_SERVICEACCOUNT_EMAIL}}"
           WORKLOAD_ID_SERVICEACCOUNT_EMAIL: "${{secrets.WORKLOAD_ID_SERVICEACCOUNT_EMAIL}}"
           TFSTATE_STORAGE_BUCKET: "${{secrets.TFSTATE_STORAGE_BUCKET}}"