Fix windows test on writing the TLE database

[pnuu]

This is an attempt at fixing a failing test on Windows.

• [ ] Closes #xxxx
• [ ] Tests added
• [ ] Tests passed
• [ ] Passes flake8 pyorbital
• [ ] Fully documented

[codecov[bot]]

Codecov Report

Merging #107 (931370f) into main (f7038d4) will decrease coverage by 0.04%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #107      +/-   ##
==========================================
- Coverage   87.03%   86.99%   -0.05%     
==========================================
  Files          13       12       -1     
  Lines        2052     2045       -7     
==========================================
- Hits         1786     1779       -7     
  Misses        266      266              

Flag	Coverage Δ
unittests	86.99% <100.00%> (-0.05%)	:arrow_down:

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Impacted Files	Coverage Δ
pyorbital/tests/test_tlefile.py	98.00% <100.00%> (+0.01%)	:arrow_up:
pyorbital/__init__.py

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