Update Github templates (#8593)

.github/ISSUE_TEMPLATE/bug_report.md

@@ -1,10 +1,11 @@
-##### Issue type
-<!-- Pick one below and delete others -->
- - Bug report
- - Feature request
- - Documentation issue
- - Build issue
- 
+---
+name: Bug report
+about: Create a report to help us improve
+title: ''
+labels: Unconfirmed bug
+assignees: ''
+---
+
 ##### Minetest version
 <!--
 Paste Minetest version between quotes below

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,25 @@
+---
+name: Feature request
+about: Suggest an idea for this project
+title: ''
+labels: Feature request
+assignees: ''
+---
+
+## Problem
+
+A clear and concise description of what the problem is.
+ie: Why is this needed?
+Ex. I'm always frustrated when [...]
+
+## Solutions
+
+A clear and concise description of what you want to happen.
+
+## Alternatives
+
+A clear and concise description of any alternative solutions or features you've considered.
+
+## Additional context
+
+Add any other context or screenshots about the feature request here.

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,19 @@
+Add compact, short information about your PR for easier understanding:
+
+- Goal of the PR
+- How does the PR work?
+- Does it resolve any reported issue?
+- If not a bug fix, why is this PR needed? What usecases does it solve?
+
+## To do
+
+This PR is a Work in Progress / Ready for Review.
+<!-- ^ delete one -->
+
+- [ ] List
+- [ ] Things
+- [ ] To do
+
+## How to test
+
+<!-- Example code or instructions -->

.github/SECURITY.md

@@ -0,0 +1,20 @@
+# Security Policy
+
+## Supported Versions
+
+We only support the latest stable version for security issues.
+See the [releases page](https://github.com/minetest/minetest/releases).
+
+## Reporting a Vulnerability
+
+We ask that you report vulnerabilities privately, by contacting a core developer,
+to give us time to fix them. You can do that by emailing one of the following addresses:
+
+* celeron55@gmail.com
+* rubenwardy@minetest.net
+
+Depending on severity, we will either create a private issue for the vulnerability
+and release a patch version of Minetest, or give you permission to file the issue publicly.
+
+For more information on the justification of this policy, see
+[Responsible Disclosure](https://en.wikipedia.org/wiki/Responsible_disclosure).