add change note

2021-01-21 11:08:39 +01:00 · 2021-01-21 11:08:39 +01:00 · a9a901d1e2
--- a/javascript/change-notes/2021-01-21-type-inference-compound.md
+++ b/javascript/change-notes/2021-01-21-type-inference-compound.md
@ -0,0 +1,2 @@
+lgtm,codescanning
+* Added support for modern compound assignments (`||=`, `&&=`, and `??=`) in the type inference.