chore: update sponsors (#2514)

Author: yyx990803

themes/vue/_config.yml

@@ -55,9 +55,6 @@ gold_sponsors:
   - url: 'https://tidelift.com/subscription/npm/vue'
     img: tidelift.png
     name: Tidelift
-  - url: 'https://opteo.com/vue'
-    img: opteo.png
-    name: Opteo
   - url: 'https://devsquad.com/'
     img: devsquad.png
     name: DevSquad
@@ -88,21 +85,12 @@ gold_sponsors:
   - url: 'https://usave.co.uk/utilities/broadband'
     img: usave.png
     name: usave
-  - url: 'https://www.dailynow.co/'
-    img: daily.png
-    name: Daily
-  - url: 'https://storekit.com'
-    img: storekit.png
-    name: StoreKit
   - url: 'http://www.pullrequest.com'
     img: pullrequest.svg
     name: PullRequest
   - url: 'https://unicorn.io/'
     img: unicorn_io.png
     name: Unicorn.io
-  - url: ' https://programmers.io/vuejs/'
-    img: programmers_io.png
-    name: Programmers.io
   - url: 'https://www.vuescreencasts.com/'
     img: happy_programmer_llc.png
     name: Happy Programmer LLC