.github: by default assign issues to me (#549)

.github/blunderbuss.yml

diff --git a/.github/blunderbuss.yml b/.github/blunderbuss.yml
new file mode 100644
index 0000000..cbf5c74
--- /dev/null
+++ b/.github/blunderbuss.yml
@@ -0,0 +1,2 @@
+assign_issues:
+- codyoss