Fix some random front matter leftovers from old docs (#56)

Author: eiriksm

docs/configuration/default_branch.mdx

@@ -2,7 +2,7 @@
 title: "default_branch"
 date: 2019-07-01T17:46:00+02:00
 anchor: "default_branch"
-weight: 
+weight:
 ---
 
 ## Configuration
@@ -39,7 +39,7 @@ If a project uses the `main` branch as the default branch, and you want the pull
   "description": "My awesome project",
   "extra": {
     "violinist": {
-// highlight-next-line
+      // highlight-next-line
       "default_branch": "develop"
     }
   }

docs/introduction/repository-access-self-hosted.mdx

@@ -1,6 +1,5 @@
 ---
 title: "Repository access for on-prem / self hosted violinist update check runners"
-date: 2018-03-25T10:50:02+02:00
 ---
 
 > This information relates to the _on-prem / Self Hosted_ version, which is _not_ [violinist.io](https://violinist.io) - a SaaS providing automated update checks for Composer / PHP. This information only applies to running update runner with the on-prem / Self Hosted version.