8.19: update versions to 8.19.18 (#21101)

Co-authored-by: obltmachine <150269514+obltmachine@users.noreply.github.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>

Author: 3 people

cmd/intake-receiver/version.go

@@ -18,4 +18,4 @@
 package main
 
 // version matches the APM Server's version
-const version = "8.19.17"
+const version = "8.19.18"

internal/version/version.go

@@ -18,4 +18,4 @@
 package version
 
 // Version holds the APM Server version.
-const Version = "8.19.17"
+const Version = "8.19.18"