When the username/password concat is too long, encryptPassword fails

[Hainish]

When the combined username/password combo is longer than 84 characters, an error is encountered when calling login:

Traceback (most recent call last):
  File "test.py", line 7, in <module>
    api.login(email=mail, password=passwd)
  File "/home/user/workspace/googleplay-api/gpapi/googleplay.py", line 214, in login
    encryptedPass = self.encryptPassword(email, password).decode('utf-8')
  File "/home/user/workspace/googleplay-api/gpapi/googleplay.py", line 124, in encryptPassword
    label=None
  File "/usr/lib/python3/dist-packages/cryptography/hazmat/backends/openssl/rsa.py", line 448, in encrypt
    return _enc_dec_rsa(self._backend, self, plaintext, padding)
  File "/usr/lib/python3/dist-packages/cryptography/hazmat/backends/openssl/rsa.py", line 68, in _enc_dec_rsa
    return _enc_dec_rsa_pkey_ctx(backend, key, data, padding_enum, padding)
  File "/usr/lib/python3/dist-packages/cryptography/hazmat/backends/openssl/rsa.py", line 122, in _enc_dec_rsa_pkey_ctx
    _handle_rsa_enc_dec_error(backend, key)
  File "/usr/lib/python3/dist-packages/cryptography/hazmat/backends/openssl/rsa.py", line 136, in _handle_rsa_enc_dec_error
    "Data too long for key size. Encrypt less data or use a "
ValueError: Data too long for key size. Encrypt less data or use a larger key size.