docs: Correct Electron 9 stable date (#22258)

2020-02-19 15:10:19 -08:00 · 2020-02-19 15:10:19 -08:00 · cdc13919b2
--- a/docs/tutorial/electron-timelines.md
+++ b/docs/tutorial/electron-timelines.md
@ -14,5 +14,5 @@
 | 6.0.0 | 2019-05-01 | 2019-07-30 | M76 | v12 |
 | 7.0.0 | 2019-08-01 | 2019-10-22 | M78 | v12 |
 | 8.0.0 | 2019-10-24 | 2020-02-04 | M80 | v12 |
-| 9.0.0 | 2020-02-06 | 2020-03-12 | M82 | v12 |
+| 9.0.0 | 2020-02-06 | 2020-04-28 | M82 | v12 |
 | 10.0.0 | TBD | TBD | TBD | TBD |