curl: add User-Agent and update README

Better to use the `-o`, `--output` flag than redirect stdout because
that will omit any `-w` flags that you may have set in e.g. `.curlrc`.

Author: kevinburkesegment

README.md

@@ -45,7 +45,7 @@ This section records common use cases for this kubectl plugin.
 ### Collecting profiles of Go programs
 
 ```
-$ kubectl curl "http://{pod}/debug/pprof/profile?debug=1&seconds=10" > ./profile
+$ kubectl curl -o profile "http://{pod}/debug/pprof/profile?debug=1&seconds=10"
 $ go tool pprof -http :6060 ./profile
 ```
 

curl.go

@@ -96,7 +96,9 @@ func main() {
 }
 
 func run(ctx context.Context) error {
-	cArgs := make([]string, 0)
+	cArgs := []string{
+		"--header", "User-Agent: kubectl-curl",
+	}
 	flags.ParseAll(os.Args[1:], func(flag *pflag.Flag, value string) error {
 		if flag.Name == "silent" {
 			return nil // --silent is added later to all curl arguments so don't add here
@@ -239,7 +241,7 @@ func run(ctx context.Context) error {
 		}
 	}()
 
-	log.Printf("waiting for port fowarding to be established")
+	log.Printf("waiting for port forwarding to be established")
 	select {
 	case <-f.Ready:
 	case <-ctx.Done():