chore: update autorest core version (#16868)

eng/scripts/Invoke-MgmtTestgen.ps1

@@ -10,7 +10,7 @@ param(
     [switch]$format,
     [switch]$tidy,
     [string]$config = "autorest.md",
-    [string]$autorestVersion = "3.6.2",
+    [string]$autorestVersion = "3.7.3",
     [string]$goExtension = "@autorest/go@4.0.0-preview.35",
     [string]$testExtension = "@autorest/gotest@1.3.0",
     [string]$outputFolder