Add CODEOWNERS file (#139)

Author: nkzou

.github/CODEOWNERS

@@ -0,0 +1,8 @@
+# See https://help.github.com/articles/about-codeowners/ for syntax
+# Rules are matched bottom-to-top, so one team can own subdirectories
+# and another team can own the rest of the directory.
+
+# All your base
+*                       @DataDog/api-clients
+LICENSE                 @DataDog/documentation @DataDog/api-clients
+NOTICE                  @DataDog/documentation @DataDog/api-clients