fix test_github_merge_pr by using more recent easyconfig PR

[boegel]

fix for:

======================================================================
FAIL: test_github_merge_pr (test.framework.options.CommandLineOptionsTest)
Test use of --merge-pr (dry run)
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Traceback (most recent call last):
  File "/Volumes/work/EasyBuild/easybuild-framework/test/framework/options.py", line 5190, in test_github_merge_pr
    self.assertEqual(stderr.strip(), expected_stderr)
  File "/Volumes/work/EasyBuild/easybuild-framework/easybuild/base/testing.py", line 89, in assertEqual
    super().assertEqual(a, b, msg=msg)
AssertionError: '* test suite passes: (status: None) => no[110 chars]way)' != ''
- * test suite passes: (status: None) => not eligible for merging!
-
- WARNING: Review indicates this PR should not be merged (use -f/--force to do so anyway)

----------------------------------------------------------------------

nothing unusual, we need to move to a more recent PR on a semi-regular basis, see also:

• use more recent easyblocks PR in test_github_merge_pr #4414
• fix test_github_merge_pr by using more recent easyconfigs PR #4470
• fix test_github_merge_pr by using more recent easyblocks PR #5160

[Micket]

lgtm