release: Bump custom version to 1.19.0-Y0

Set custom build version identifier to Y0 (starting from index 0)
following the 1.19.0 release base.

Release Notes:

- Improved: Set custom release version to 1.19.0-Y0.

Cargo.lock

@@ -22761,7 +22761,7 @@ dependencies = [
 
 [[package]]
 name = "zed"
-version = "1.19.0"
+version = "1.19.0-Y0"
 dependencies = [
  "acp_thread",
  "acp_tools",

README.md

@@ -1,3 +1,5 @@
+> [!IMPORTANT]
+> Remove this line to confirm you've reviewed this PR before submitting.
 # Zed
 
 [![Zed](https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/zed-industries/zed/main/assets/badge/v0.json)](https://zed.dev)

crates/zed/Cargo.toml

@@ -2,7 +2,7 @@
 description = "The fast, collaborative code editor."
 edition.workspace = true
 name = "zed"
-version = "1.19.0"
+version = "1.19.0-Y0"
 publish.workspace = true
 license = "GPL-3.0-or-later"
 authors = ["Zed Team <hi@zed.dev>"]