maintenance: add CODEOWNERS file

.github/CODEOWNERS

@@ -0,0 +1,9 @@
+
+# These owners will be the default owners for everything in the
+# repo. Unless a later match takes precedence, owners listed here
+# will be requested for review when someone opens a pull request.
+*       @edaniszewski
+
+# Order is important; the last matching pattern takes the most
+# precedence. Additional matches may be added below (e.g. *.py
+# for pull requests that only modify Python files).