Fix Sentry "Unsupported media type 'application/json, application/json' in request" (#224)

* sentry: do not send Content-Type: application/json twice

The header is already set by called Httpie library. Calling ::header just adds a new header, does not do any replace.

Sentry does not recognize the request when we send the headers twice and fails with error:
```
  [RuntimeException] on [factcool-www3.superhosting.cz]
  Unable to create a release: Array
  (
  [detail] => Unsupported media type 'application/json, application/json' in request.
  )
```

* changelog: update

Author: hranicka

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 ### Added
 - Add APCu support in cachetool recipe
+- Fixed Sentry deployment recipe, updated to work with latest deployer/deployer
 
 ## 6.2.0
 [6.1.0...6.2.0](https://github.com/deployphp/recipes/compare/6.1.0...6.2.0)

recipe/sentry.php

@@ -82,7 +82,6 @@ static function (&$value) use ($config) {
             $releasesApiUrl
         )
             ->header(sprintf('Authorization: Bearer %s', $config['token']))
-            ->header('Content-Type: application/json')
             ->body($releaseData)
             ->getJson();
 
@@ -113,7 +112,6 @@ static function (&$value) use ($config) {
             $releasesApiUrl . $response['version'] . '/deploys/'
         )
             ->header(sprintf('Authorization: Bearer %s', $config['token']))
-            ->header('Content-Type: application/json')
             ->body($deployData)
             ->getJson();