use more recent easyblocks PR in test_github_merge_pr

[boegel]

fix for broken test because commit status is no longer available (so test suite passes fails with status: None):

FAIL: test_github_merge_pr (__main__.CommandLineOptionsTest)
Test use of --merge-pr (dry run)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Volumes/work/easybuild-framework/easybuild/base/testing.py", line 97, in assertEqual
    super(TestCase, self).assertEqual(a, b)
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.9/lib/python3.9/unittest/case.py", line 831, in assertEqual
    assertion_func(first, second, 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)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Volumes/work/easybuild-framework/test/framework/options.py", line 4831, in test_github_merge_pr
    self.assertEqual(stderr.strip(), '')
  File "/Volumes/work/easybuild-framework/easybuild/base/testing.py", line 119, in assertEqual
    raise AssertionError("%s:\nDIFF%s:\n%s" % (msg, limit, ''.join(diff[:self.ASSERT_MAX_DIFF])))
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):
DIFF:
- * test suite passes: (status: None) => not eligible for merging!
-

[zao]

LGTM.