[libbeat] Update lookslike to 0.3.0 (elastic#13498)

Updates the go-lookslike library we maintain to 0.3.0 which uses a much improved reflection strategy. This fixed an issue in the last release where Strict() which checked for extra fields wasn't working. As a result some of our tests developed since then didn't assert that the new fields added in elastic#13022 were actually valid. Those tests are fixed in this PR.

NOTICE.txt

@@ -861,8 +861,8 @@ Apache License 2.0
 
 --------------------------------------------------------------------
 Dependency: github.com/elastic/go-lookslike
-Version: v0.2.0
-Revision: 807124eb9fc6684949aa99744577175fd6bac4fd
+Version: =v0.3.0
+Revision: 747dc7db1c961662d8e225a42af6c3859a1a0f1d
 License type (autodetected): Apache-2.0
 ./vendor/github.com/elastic/go-lookslike/LICENSE:
 --------------------------------------------------------------------

heartbeat/monitors/active/http/http_test.go

@@ -41,6 +41,8 @@ import (
 	btesting "github.com/elastic/beats/libbeat/testing"
 	"github.com/elastic/go-lookslike"
 	"github.com/elastic/go-lookslike/isdef"
+	"github.com/elastic/go-lookslike/llpath"
+	"github.com/elastic/go-lookslike/llresult"
 	"github.com/elastic/go-lookslike/testslike"
 	"github.com/elastic/go-lookslike/validator"
 )
@@ -102,7 +104,21 @@ func respondingHTTPChecks(url string, statusCode int) validator.Validator {
 		httpBaseChecks(url),
 		lookslike.MustCompile(map[string]interface{}{
 			"http": map[string]interface{}{
-				"response.status_code":   statusCode,
+				"response.status_code": statusCode,
+				"response.body.hash":   isdef.IsString,
+				// TODO add this isdef to lookslike in a robust way
+				"response.body.bytes": isdef.Is("an int64 greater than 0", func(path llpath.Path, v interface{}) *llresult.Results {
+					raw, ok := v.(int64)
+					if !ok {
+						return llresult.SimpleResult(path, false, "%s is not an int64", reflect.TypeOf(v))
+					}
+					if raw >= 0 {
+						return llresult.ValidResult(path)
+					}
+
+					return llresult.SimpleResult(path, false, "value %v not >= 0 ", raw)
+
+				}),
 				"rtt.content.us":         isdef.IsDuration,
 				"rtt.response_header.us": isdef.IsDuration,
 				"rtt.total.us":           isdef.IsDuration,