chore(release): Java prod release doesn't always check out main branch (

#1028)

codebuild/release/release-prod.yml

@@ -4,8 +4,6 @@
 version: 0.2
 
 env:
-  variables:
-    BRANCH: "main"
   parameter-store:
     ACCOUNT: /CodeBuild/AccountId
   secrets-manager:
@@ -33,7 +31,6 @@ phases:
       - cd aws-cryptographic-material-providers-library/
   pre_build:
     commands:
-      - git checkout $BRANCH
       - aws secretsmanager get-secret-value --region us-west-2 --secret-id Maven-GPG-Keys-Release --query SecretBinary --output text | base64 -d > ~/mvn_gpg.tgz
       - tar -xvf ~/mvn_gpg.tgz -C ~
       # Create default location where GPG looks for creds and keys