Repository: traefik/traefik (language: go)

Issue:
v3.0.0-rc1 - configfile is ignored
### Welcome!

- [X] Yes, I've searched similar issues on [GitHub](https://github.com/traefik/traefik/issues) and didn't find any.
- [X] Yes, I've searched similar issues on the [Traefik community forum](https://community.traefik.io) and didn't find any.

### What did you do?

i try to run latest traefik with static configuration file. latest version seems to ignore configfile parameter and try to run default configuration.

### What did you see instead?

``` 
./traefik  --configfile ./cnf.yaml
2024-02-16T00:49:30Z ERR Command error error="command traefik error: error while building entryPoint http: error preparing server: error opening listener: listen tcp :80: bind: permission denied"
```

when running with 3.0.0-beta5 output is:
```
./traefik  --configfile ./cnf.yaml
2024-02-16T00:52:17Z INF Traefik version 3.0.0-beta5 built on 2023-11-29T15:14:06Z version=3.0.0-beta5
2024-02-16T00:52:17Z INF
Stats collection is disabled.
Help us improve Traefik by turning this feature on :)
More details on: https://doc.traefik.io/traefik/contributing/data-collection/

2024-02-16T00:52:17Z INF Starting provider aggregator aggregator.ProviderAggregator
2024-02-16T00:52:17Z INF Starting provider *traefik.Provider
2024-02-16T00:52:17Z INF Starting provider *acme.ChallengeTLSALPN
``` 


### What version of Traefik are you using?

Version:      3.0.0-rc1
Codename:     cheddar
Go version:   go1.22.0
Built:        2024-02-13T13:41:20Z
OS/Arch:      linux/amd64

### What is your environment & configuration?

```yaml
log:
  level: INFO
api:
  dashboard: true
  insecure: true

entryPoints:
  metrics:
    address: ":8082"

  web:
    address: ":6680"
    http:
      redirections:
        entrypoint:
          to: websecure
          scheme: https

  websecure:
    address: ":6443"

metrics:
  prometheus:
    entryPoint: metrics
    addRoutersLabels: true
    addServicesLabels: true
```


### If applicable, please paste the log output in DEBUG level

_No response_


Discussion / hints:

Fix patch:
diff --git a/pkg/cli/deprecation.go b/pkg/cli/deprecation.go
index 379d986a7b..98fc1d1c10 100644
--- a/pkg/cli/deprecation.go
+++ b/pkg/cli/deprecation.go
@@ -24,16 +24,19 @@ func (d DeprecationLoader) Load(args []string, cmd *cli.Command) (bool, error) {
 }
 
 // logDeprecation prints deprecation hints and returns whether incompatible deprecated options need to be removed.
-func logDeprecation(traefikConfiguration interface{}, args []string) bool {
+func logDeprecation(traefikConfiguration interface{}, arguments []string) bool {
 	// This part doesn't handle properly a flag defined like this:
 	// --accesslog true
 	// where `true` could be considered as a new argument.
-	// This is not really an issue with the deprecation loader since it will filter the unknown nodes later in this
-	// function.
-	for i, arg := range args {
+	// This is not really an issue with the deprecation loader since it will filter the unknown nodes later in this function.
+	var args []string
+	for _, arg := range arguments {
 		if !strings.Contains(arg, "=") {
-			args[i] = arg + "=true"
+			args = append(args, arg+"=true")
+			continue
 		}
+
+		args = append(args, arg)
 	}
 
 	labels, err := flag.Parse(args, nil)


Test patch: