[Bug] Intermittently failing unit test for multitaper PSD

[rjurkus]

Describe the bug

Occasionally, the test_multitaper_psd_behavior fails.

To Reproduce

1. Run the test_spectral.py multiple times

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FAIL: test_multitaper_psd_behavior (elephant.test.test_spectral.MultitaperPSDTestCase)
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Traceback (most recent call last):
  File "/home/jurkus/repositories/elephant/elephant/test/test_spectral.py", line 216, in test_multitaper_psd_behavior
    self.assertEqual(freqs[psd.argmax()], signal_freq)
AssertionError: array(99.8) * Hz != 100.0

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Ran 24 tests in 1.365s

FAILED (failures=1)

Expected behavior
The test should always pass.

Environment

• OS (e.g., Linux): Ubuntu 18.04.6 LTS
• How you installed elephant (conda, pip, source): pip, source
• Python version: 3.7.3
• neo python package version: 0.10.0
• elephant python package version: 0.12.0b1