Bump to Go 1.20.12

- go1.20.11 (released 2023-11-07) includes security fixes to the path/filepath package, as well as bug fixes to the linker and the net/http package.
- go1.20.12 (released 2023-12-05) includes security fixes to the go command, and the net/http and path/filepath packages, as well as bug fixes to the compiler and the go command.

Signed-off-by: Richard Wall <richard.wall@venafi.com>

make/tools.mk

@@ -75,7 +75,7 @@ KUBEBUILDER_ASSETS_VERSION=1.28.0
 TOOLS += etcd=$(KUBEBUILDER_ASSETS_VERSION)
 TOOLS += kube-apiserver=$(KUBEBUILDER_ASSETS_VERSION)
 
-VENDORED_GO_VERSION := 1.20.10
+VENDORED_GO_VERSION := 1.20.12
 
 # When switching branches which use different versions of the tools, we
 # need a way to re-trigger the symlinking from $(BINDIR)/downloaded to $(BINDIR)/tools.