chore: add default assignee for issues (googleapis#435)

Author: zoercai

java-spanner-jdbc/.github/blunderbuss.yml

@@ -1,7 +1,9 @@
 # Configuration for the Blunderbuss GitHub app. For more info see
 # https://github.com/googleapis/repo-automation-bots/tree/master/packages/blunderbuss
+assign_issues:
+  - thiagotnunes
 assign_prs_by:
 - labels:
   - samples
   to:
-  - googleapis/java-samples-reviewers
+  - googleapis/java-samples-reviewers

java-spanner-jdbc/synth.py

@@ -20,7 +20,8 @@
 
 java.common_templates(excludes=[
     'README.md',
-    
+
     '.github/release-please.yml',
     '.github/sync-repo-settings.yaml',
+    '.github/blunderbuss.yml',
 ])