chore: we're now hacking on v3.19.0-alpha.3

Part of ooni/probe#2524

Author: bassosimone

internal/version/version.go

@@ -2,4 +2,4 @@
 package version
 
 // Version is the ooniprobe version.
-const Version = "3.19.0-alpha.2"
+const Version = "3.19.0-alpha.3"