docs: pull request template

.github/pull_request_template.md

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+# Description
+
+<!-- Please include a summary of the change, motivation and context. It it's a but fix, add a reference in format #issue_number -->
+
+# Type of change
+
+<!-- Please put X into brackers of required option OR delete options that are not relevant -->
+
+- [ ] Bug fix
+- [ ] New feature
+- [ ] Refactoring / style
+- [ ] Documentation update / chore
+- [ ] Other (please describe)
+
+# Versioning
+
+<!-- Update the version if you want the PR to be merged fast. Currently it's a manual 3-steps process:
+  * update version in `versioning.js` using semver principle. Just set the next patch (for fixes) or minor version (for new features)
+  * for all changed files update hash (the part after `?`) in place where file is requested (usually it's `index.html`)
+  * if the change can be really interesting for end-users, describe it inside the `showUpdateWindow()` function in `versioning.js` -->
+
+- [ ] Version is updated
+- [ ] Changed files hash is updated