Enforced UTF-8 encoding of written bom.xml file

[TTMaZa]

To prevent Exceptions such as this:

Traceback (most recent call last):
  File "c:\python\python_3.7.4_64bit\Lib\runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "c:\python\python_3.7.4_64bit\Lib\runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "C:\Data\.virtualenvs\cycloneDX-fCyJ5Voc\Scripts\cyclonedx-py.exe\__main__.py", line 9, in <module>
  File "c:\Data\.virtualenvs\cyclonedx-fcyj5voc\lib\site-packages\cyclonedx\cli\generateBom.py", line 140, in main
    text_file.write(bom_xml)
  File "c:\Data\.virtualenvs\cyclonedx-fcyj5voc\lib\encodings\cp1252.py", line 19, in encode
    return codecs.charmap_encode(input,self.errors,encoding_table)[0]
UnicodeEncodeError: 'charmap' codec can't encode character '\u0103' in position 57206: character maps to <undefined>