build with Go 1.21.1 (#33830)

The Go 1.21.1 release includes some security fixes. These security fixes
do not affect any functionality currently used by Terraform at run time
or build time.

The Go 1.21.1 release fixes a security vulnerability affecting the new
"toolchain" directive in the go.mod file, which Terraform does not use
at present.
Nevertheless development and build environments should be upgraded to Go 1.21.1 to mitigate risk from accidental or experimental use of this directive.

.go-version

@@ -1 +1 @@
-1.21.0
+1.21.1

go.mod

@@ -272,4 +272,4 @@ require (
 	sigs.k8s.io/yaml v1.2.0 // indirect
 )
 
-go 1.21.0
+go 1.21.1