Pull the role from Secrets, not vars

gh-7

My last build failed with:

Error: Credentials could not be loaded, please check your action inputs:
Could not load credentials from any providers

But an example here:

https://github.com/aws-actions/configure-aws-credentials#assumerole-with-static-iam-credentials-in-repository-secrets

has the role-to-assume pulled from a Secret.

.github/workflows/main.yml

@@ -76,7 +76,7 @@ jobs:
       - name: Configure AWS Credentials
         uses: aws-actions/configure-aws-credentials@v2
         with:
-          role-to-assume: ${{ vars.TEST_ROLE }}
+          role-to-assume: ${{ secrets.TEST_ACCOUNT_ROLE }}
           aws-region: us-west-2
       - name: Deploy the app stack to the test account
         working-directory: infra