chore: fix PR template links to execution-specs (ethereum#2035)

Author: danceratopz

.github/PULL_REQUEST_TEMPLATE.md

@@ -10,16 +10,17 @@ N/A.
 <!-- Please check off all required items. For those that don't apply remove them accordingly. -->
 
 - [ ] All: Ran fast `tox` checks to avoid unnecessary CI fails, see also [Code Standards](https://eest.ethereum.org/main/getting_started/code_standards/) and [Enabling Pre-commit Checks](https://eest.ethereum.org/main/dev/precommit/):
+
     ```console
     uvx tox -e static
     ```
+
 - [ ] All: PR title adheres to the [repo standard](https://eest.ethereum.org/main/getting_started/contributing/?h=contri#commit-messages-issue-and-pr-titles) - it will be used as the squash commit message and should start `type(scope):`.
-- [ ] All: Considered adding an entry to [CHANGELOG.md](/ethereum/execution-spec-tests/blob/main/docs/CHANGELOG.md).
-- [ ] All: Considered updating the online docs in the [./docs/](/ethereum/execution-spec-tests/blob/main/docs/) directory.
+- [ ] All: Considered updating the online docs in the [./docs/](/ethereum/execution-specs/blob/HEAD/docs/) directory.
 - [ ] All: Set appropriate labels for the changes (only maintainers can apply labels).
 - [ ] Tests: Ran `mkdocs serve` locally and verified the auto-generated docs for new tests in the [Test Case Reference](https://eest.ethereum.org/main/tests/) are correctly formatted.
-- [ ] Tests: For PRs implementing a missed test case, update the [post-mortem document](/ethereum/execution-spec-tests/blob/main/docs/writing_tests/post_mortems.md) to add an entry the list.
-- [ ] Ported Tests: All converted JSON/YML tests from [ethereum/tests](/ethereum/tests) or [tests/static](/ethereum/execution-spec-tests/blob/main/tests/static) have been assigned `@ported_from` marker.
+- [ ] Tests: For PRs implementing a missed test case, update the [post-mortem document](/ethereum/execution-specs/blob/HEAD/docs/writing_tests/post_mortems.md) to add an entry the list.
+- [ ] Ported Tests: All converted JSON/YML tests from [ethereum/tests](/ethereum/tests) or [tests/static](/ethereum/execution-specs/blob/HEAD/tests/static) have been assigned `@ported_from` marker.
 
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