fix chinese pinyin phonemes

[eginhard]

Copied from coqui-ai#3511:

'g' does not exist in the phonemes, it should be 'ɡ'.

# DEFAULT SET OF IPA PHONEMES
# Phonemes definition (All IPA characters)
_vowels = "iyɨʉɯuɪʏʊeøɘəɵɤoɛœɜɞʌɔæɐaɶɑɒᵻ"
_non_pulmonic_consonants = "ʘɓǀɗǃʄǂɠǁʛ"
_pulmonic_consonants = "pbtdʈɖcɟkɡqɢʔɴŋɲɳnɱmʙrʀⱱɾɽɸβfvθðszʃʒʂʐçʝxɣχʁħʕhɦɬɮʋɹɻjɰlɭʎʟ"
_suprasegmentals = "ˈˌːˑ"
_other_symbols = "ʍwɥʜʢʡɕʑɺɧʲ"
_diacrilics = "ɚ˞ɫ"
_phonemes = _vowels + _non_pulmonic_consonants + _pulmonic_consonants + _suprasegmentals + _other_symbols + _diacrilics