Pin PKI test suite to zlint v3.6.2 (#27964)

- Avoid this error for now

zlint_test.go:149: got unexpected error from test e_subj_orgunit_in_ca_cert: map[details:The OU attribute in the Subject is prohibited in Root and TLS CA certificates result:error]

builtin/logical/pkiext/zlint_test.go

@@ -23,7 +23,7 @@ func buildZLintContainer(t *testing.T) {
 	containerfile := `
 FROM docker.mirror.hashicorp.services/library/golang:latest
 
-RUN go install github.com/zmap/zlint/v3/cmd/zlint@latest
+RUN go install github.com/zmap/zlint/v3/cmd/zlint@v3.6.2
 `
 
 	bCtx := docker.NewBuildContext()