Update EC2 instance type to c8i.8xlarge and add AWS region parameter.

Author: yegor256

.github/workflows/ec2.yml

@@ -21,14 +21,15 @@ jobs:
         with:
           aws-access-key-id: ${{ secrets.AWS_KEY }}
           aws-secret-access-key: ${{ secrets.AWS_SECRET }}
+          aws-region: ${{ secrets.AWS_REGION }}
       - id: start
         uses: machulav/ec2-github-runner@v2
         with:
           mode: start
           aws-resource-tags: '[{"Key":"Name","Value":"eo-runtime"}]'
           github-token: ${{ secrets.AWS_PAT }}
           ec2-image-id: ${{ secrets.AWS_AMI }}
-          ec2-instance-type: c8i.16xlarge
+          ec2-instance-type: c8i.8xlarge
           subnet-id: ${{ secrets.AWS_SUBNET }}
           security-group-id: ${{ secrets.AWS_SGROUP }}
   runtime:
@@ -70,6 +71,7 @@ jobs:
         with:
           aws-access-key-id: ${{ secrets.AWS_KEY }}
           aws-secret-access-key: ${{ secrets.AWS_SECRET }}
+          aws-region: ${{ secrets.AWS_REGION }}
       - uses: machulav/ec2-github-runner@v2
         with:
           mode: stop