chore: import upstream snapshot with attribution

.github/pull_request_template.md

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+### Introduction
+To contribute code to the Pathway Live Data Framework project, start by discussing your proposed changes on Discord or by filing an issue. 
+Once approved, follow the fork + pull request model against the main branch, ensuring you've signed the contributor license agreement.
+
+### Context
+<!--- Why is this change required? What problem does it solve? -->
+
+### How has this been tested?
+<!--- Please describe in detail how you tested your changes. -->
+
+### Types of changes
+<!--- What types of changes does your code introduce? Put an `x` in all the boxes that apply: -->
+- [ ] Bug fix (non-breaking change which fixes an issue)
+- [ ] New feature or improvement (non-breaking change which adds functionality)
+- [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
+
+### Related issue(s):
+1. 
+2.
+3.
+
+### Checklist:
+<!--- Go over all the following points, and put an `x` in all the boxes that apply. -->
+<!--- If you're unsure about any of these, don't hesitate to ask. We're here to help! -->
+- [ ] My code follows the code style of this project,
+- [ ] My change requires a change to the documentation,
+- [ ] I described the modification in the CHANGELOG.md file.