Link to readme from pull request template

Author: dergoegge

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,6 +1,3 @@
-If you are adding fuzz seeds, please "merge" the seeds before submitting this
-pull request, then remove the instruction text here.
-
-You can use the libFuzzer option `-merge=1` (recommended with
-`-use_value_profile=1`) or the `--m_dir` option of the fuzz runner:
-https://github.com/bitcoin/bitcoin/blob/master/test/fuzz/test_runner.py
+Please see the
+[README.md](https://github.com/bitcoin-core/qa-assets/blob/main/README.md) for
+instructions on how to contribute new inputs.