CaseClauseError raised by JOSE.JWT.peek_protected/1 with malformed token

[exlee]

I stumbled upon following condition when malformed token was provided (extra "e" at the beginning).

Output is for 1.11.2 however outcome is the same for 1.11.6.

iex(1)> jwt_token = "eeyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c"
iex(2)> JOSE.JWT.peek_protected(jwt_string)
** (CaseClauseError) no case clause matching: "9"
    (jose 1.11.2) src/base/jose_base64url.erl:222: :jose_base64url.decode!/2
    (jose 1.11.2) src/jwt/jose_jwt.erl:162: :jose_jwt.peek_protected/1
    (jose 1.11.2) lib/jose/jwt.ex:191: JOSE.JWT.peek_protected/1
    iex:2: (file)

Not sure if there's any validation that could be done before trying to peek, though.
My expectations for such scenarios would be an :error return or more descriptive throw (e.g. UndecodableTokenError).

Seems to be similar to #22