pathogen-repo-build: rename setup-aws-credentials anchor

Renamed to `setup-aws-batch-credentials` in preparation for adding
another step that sets up AWS credentials for the runtime.

The new step for setting up runtime AWS credentials probably won't need
an anchor as it should only run once before the build starts. I
just wanted to be specific with the existing anchor name to prevent any
potential confusion.

.github/workflows/pathogen-repo-build.yaml.in

@@ -218,7 +218,7 @@ jobs:
           | "$NEXTSTRAIN_GITHUB_DIR"/bin/json-to-envvars
           | tee -a "$GITHUB_ENV"
 
-      - &setup-aws-credentials
+      - &setup-aws-batch-credentials
         if: inputs.runtime == 'aws-batch'
         uses: aws-actions/configure-aws-credentials@v4
         with:
@@ -294,7 +294,7 @@ jobs:
     steps:
       # Uses needs.workflow-context.outputs
       - *checkout-workflow-support
-      - *setup-aws-credentials
+      - *setup-aws-batch-credentials
       - *setup-runtime
 
       - id: attach
@@ -379,7 +379,7 @@ jobs:
     steps:
       # Uses needs.workflow-context.outputs
       - *checkout-workflow-support
-      - *setup-aws-credentials
+      - *setup-aws-batch-credentials
       - *setup-runtime
 
       - id: cancel