Raise go.mod version of build/make/tools/rbcrun

Raising the go.mod version to 1.17 or higher enables module graph
pruning (https://go.dev/ref/mod#graph-pruning), which prevents the
go tools like "go build ./..." from loading unused transitive
dependencies, including ones that are missing from our tree.

Bug: 314133304
Test: prebuilts/build-tools/build-prebuilts.sh
Change-Id: If1cc0fda1dc744e65fc3367b7f44b8c91230e5ce
diff --git a/tools/rbcrun/go.mod b/tools/rbcrun/go.mod
index 5ae2972..6e99ce9 100644
--- a/tools/rbcrun/go.mod
+++ b/tools/rbcrun/go.mod
@@ -4,4 +4,4 @@
 
 replace go.starlark.net => ../../../../external/starlark-go
 
-go 1.15
+go 1.21