Updated all dependencies one by one to go.mod - Backup and remove the vendor folder entirely and update most of the examples - next commit will contain the rest of the updated

Former-commit-id: 2791c50256c0f00d6e08a408e5cb009262c49588

_examples/experimental-handlers/casbin/middleware/main_test.go

@@ -3,7 +3,7 @@ package main
 import (
 	"testing"
 
-	"github.com/iris-contrib/httpexpect"
+	"github.com/gavv/httpexpect"
 	"github.com/kataras/iris/httptest"
 )
 

_examples/experimental-handlers/casbin/wrapper/main_test.go

@@ -3,7 +3,7 @@ package main
 import (
 	"testing"
 
-	"github.com/iris-contrib/httpexpect"
+	"github.com/gavv/httpexpect"
 	"github.com/kataras/iris/httptest"
 )
 

_examples/experimental-handlers/prometheus/simple/main.go

@@ -8,7 +8,7 @@ import (
 
 	prometheusMiddleware "github.com/iris-contrib/middleware/prometheus"
 
-	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
 func main() {
@@ -31,7 +31,7 @@ func main() {
 		ctx.Writef("Slept for %d milliseconds", sleep)
 	})
 
-	app.Get("/metrics", iris.FromStd(prometheus.Handler()))
+	app.Get("/metrics", iris.FromStd(promhttp.Handler()))
 
 	// http://localhost:8080/
 	// http://localhost:8080/anotfound

_examples/file-server/embedding-gziped-files-into-app/main_test.go

@@ -89,9 +89,10 @@ func TestEmbeddingGzipFilesIntoApp(t *testing.T) {
 		if expected, got := response.Raw().StatusCode, httptest.StatusOK; expected != got {
 			t.Fatalf("[%d] of '%s': expected %d status code but got %d", i, url, expected, got)
 		}
+		rawBody := response.Body().Raw()
 
 		func() {
-			reader, err := gzip.NewReader(bytes.NewBuffer(response.Content))
+			reader, err := gzip.NewReader(strings.NewReader(rawBody))
 			defer reader.Close()
 			if err != nil {
 				t.Fatalf("[%d] of '%s': %v", i, url, err)

_examples/http-listening/http3-quic/go.mod

@@ -0,0 +1,7 @@
+module github.com/kataras/iris/_examples/http-listening/http3-quic
+
+go 1.12
+
+require (
+    github.com/prometheus/client_golang v1.0.0
+)

_examples/http-listening/http3-quic/main.go

@@ -8,7 +8,10 @@ import (
 
 /*
 	$ go get -u github.com/lucas-clemente/quic-go/...
+	# or if you're using GO MODULES:
+	$ go get github.com/lucas-clemente/quic-go@master
 */
+
 func main() {
 	app := iris.New()