Remove '.gitpod.yml' (jenkinsci#26019)

Author: NotMyFault

.github/renovate.json

@@ -75,13 +75,6 @@
       "datasourceTemplate": "docker",
       "versioningTemplate": "loose"
     },
-    {
-      "customType": "regex",
-      "managerFilePatterns": ["/.gitpod/Dockerfile/"],
-      "matchStrings": ["ARG MAVEN_VERSION=(?<currentValue>.*?)\n"],
-      "depNameTemplate": "org.apache.maven:maven-core",
-      "datasourceTemplate": "maven"
-    },
     {
       "customType": "regex",
       "managerFilePatterns": ["/core/src/site/site.xml/"],

.gitpod.yml

@@ -83,16 +83,6 @@ Open another terminal and start a [webpack](https://webpack.js.org/) dev server,
 yarn start
 ```
 
-### Gitpod
-
-You can open this project as a [Gitpod workspace](https://www.gitpod.io/) which comes pre-configured with all the tools you will need.
-You can use IntelliJ IDEA (preferred) or VS Code (alternate) in the browser.
-
-[![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/#https://github.com/jenkinsci/jenkins)
-
-If you prefer using IntelliJ IDEA, you can setup Gitpod integration with JetBrains Gateway using the instructions on [gitpod.io](https://www.gitpod.io/docs/ides-and-editors/intellij),
-which will open the workspace in IntelliJ IDEA using JetBrains Gateway.
-
 ### Linting
 
 For linting we use a number of tools: