chore: PR Template added

Author: LuisThein

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,11 @@
+*Replace this paragraph with a description of what this PR is changing or adding, and why. Consider including before/after screenshots.*
+
+*List which issues are fixed by this PR.*
+
+## Pre-launch Checklist
+
+- [ ] I updated pubspec.yaml with an appropriate new version according to the [pub versioning philosophy].
+- [ ] I updated CHANGELOG.md to add a description of the change.
+- [ ] I updated/added relevant documentation (doc comments with `///`).
+- [ ] I added new tests to check the change I am making if a test is possible.
+- [ ] All existing and new tests are passing.