AB#2291189 Update Node version to 20.19.2 for agent (#5256)

Author: dassayantan24

src/Misc/externals.sh

@@ -26,7 +26,7 @@ NODE_VERSION="6.17.1"
 NODE10_VERSION="10.24.1"
 NODE16_VERSION="16.20.2"
 NODE16_WIN_ARM64_VERSION="16.9.1"
-NODE20_VERSION="20.18.2"
+NODE20_VERSION="20.19.2"
 MINGIT_VERSION="2.49.0"
 LFS_VERSION="3.4.0"