Repository: traefik/traefik (language: go)

Issue:
PR#9224 breaks `htransformation` plugin functionality
### 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?

While I understand that `traefik` plugins are an experimental feature, I would love to know if this is something that should be addressed by `traefik` team or the plugin author. After the changes introduced in the [PR#9224](https://github.com/traefik/traefik/pull/9224), the [htransformation](https://github.com/tomMoulard/htransformation) plugin headers manipulation functionality is broken. I added my very simple `htransformation` plugin middleware configuration to the "configuration" section of this issue. Below is an HTTPBin output of the request with `traefik` v2.8.1 (and v2.8.2 with PR#9224 reverted):

```json
{
  "args": {},
  "headers": {
    "Accept": "*/*",
    "Accept-Encoding": "gzip",
    "Host": "httpbin.org",
    "User-Agent": "curl/7.79.1",
    "X-Amzn-Trace-Id": "Root=1-62ff074f-65675efb361949c26859e958",
    "X-Forwarded-Host": "custom.localhost",
    "X-Forwarded-Server": "Alexeys-MacBook-Pro.local"
  },
  "origin": "127.0.0.1, 184.22.158.53",
  "url": "https://custom.localhost/get"
}
```

### What did you see instead?

This is the output of the same request with the same configuration, but with `traefik` v2.8.2 and v2.8.3:

```json
{
  "args": {},
  "headers": {
    "Accept": "*/*",
    "Accept-Encoding": "gzip",
    "Host": "httpbin.org",
    "User-Agent": "curl/7.79.1",
    "X-Amzn-Trace-Id": "Root=1-62ff0774-449387a219ccf1af73b91d4f",
    "X-Forwarded-Host": "custom.\u00e2\u0095\u009124\u00e2\u0095\u0091^X-Forwarded-Host",
    "X-Forwarded-Server": "Alexeys-MacBook-Pro.local"
  },
  "origin": "127.0.0.1, 184.22.158.53",
  "url": "https://custom.\u00e2\u0095\u009124\u00e2\u0095\u0091^X-Forwarded-Host/get"
}
```

### What version of Traefik are you using?

Version:      2.8.3
Codename:     cheddar
Go version:   go1.18.5
Built:        I don't remember exactly
OS/Arch:      darwin/amd64

### What is your environment & configuration?

```yaml
http:
  middlewares:
    build_client_fqdn:
      plugin:
        htransformation:
          Rules:
            - Header: X-Forwarded-Host
              Type: RewriteValueRule
              Value: "api.(.*)"
              ValueReplace: "$1"

            - Header: X-Client-Subdomain
              Type: Join
              Sep: "."
              HeaderPrefix: "^"
              Values:
                - "^X-Forwarded-Host"

            - Header: X-Client-Subdomain
              Type: Rename
              Value: X-Forwarded-Host
```

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

_No response_


Discussion / hints:
Hello @leshik,

Thanks for your interest in Traefik!

As explained [here](https://github.com/tomMoulard/htransformation/issues/34#issuecomment-1220347513), the issue does not come from traefik itself.
@tomMoulard no, it's a different issue, unrelated to the previous one. Please reopen this.

Fix patch:
diff --git a/go.mod b/go.mod
index 98b128bb08..8e4cac64df 100644
--- a/go.mod
+++ b/go.mod
@@ -55,7 +55,7 @@ require (
 	github.com/sirupsen/logrus v1.8.1
 	github.com/stretchr/testify v1.8.0
 	github.com/stvp/go-udp-testing v0.0.0-20191102171040-06b61409b154
-	github.com/traefik/paerser v0.1.8
+	github.com/traefik/paerser v0.1.9
 	github.com/traefik/yaegi v0.14.1
 	github.com/uber/jaeger-client-go v2.30.0+incompatible
 	github.com/uber/jaeger-lib v2.2.0+incompatible
diff --git a/go.sum b/go.sum
index 31044ce793..70b1a54e67 100644
--- a/go.sum
+++ b/go.sum
@@ -1903,8 +1903,8 @@ github.com/tonistiigi/units v0.0.0-20180711220420-6950e57a87ea h1:SXhTLE6pb6eld/
 github.com/tonistiigi/units v0.0.0-20180711220420-6950e57a87ea/go.mod h1:WPnis/6cRcDZSUvVmezrxJPkiO87ThFYsoUiMwWNDJk=
 github.com/tonistiigi/vt100 v0.0.0-20190402012908-ad4c4a574305 h1:y/1cL5AL2oRcfzz8CAHHhR6kDDfIOT0WEyH5k40sccM=
 github.com/tonistiigi/vt100 v0.0.0-20190402012908-ad4c4a574305/go.mod h1:gXOLibKqQTRAVuVZ9gX7G9Ykky8ll8yb4slxsEMoY0c=
-github.com/traefik/paerser v0.1.8 h1:DmX/v9KwWAFvRr5A/XQzLLfd1BSWgh710q+dZJmjZ+c=
-github.com/traefik/paerser v0.1.8/go.mod h1:Dk3Bfz6Zyj13/S8pJyRdx/FNvXlsVRVbtp0UK4ZSiA0=
+github.com/traefik/paerser v0.1.9 h1:x5hZafOt/yogLvr6upoSOYIAn2nh2GsnLb236MOzd4I=
+github.com/traefik/paerser v0.1.9/go.mod h1:Dk3Bfz6Zyj13/S8pJyRdx/FNvXlsVRVbtp0UK4ZSiA0=
 github.com/traefik/yaegi v0.14.1 h1:t0ssyzeZCWTFGd/JnVuDxH/slMQfYg+2CDD4dLW/rU0=
 github.com/traefik/yaegi v0.14.1/go.mod h1:AVRxhaI2G+nUsaM1zyktzwXn69G3t/AuTDrCiTds9p0=
 github.com/transip/gotransip/v6 v6.6.1 h1:nsCU1ErZS5G0FeOpgGXc4FsWvBff9GPswSMggsC4564=


Test patch: